T H.E U N I V E R S I T Y 0 F M I C H I G A N COLLEGE OF ENGINEERING Department of Mechanical Engineering Heat Transfer Laboratory Technical Report No. 2 BOILING OF LIQUID NITROGEN IN REDUCED GRAVITY FIELDS WITH SUBCOOLING Eugene W.e L-ewis John A,. Clark Herman Merte, Jro ORA Project- 07461 under contract with: NATIONAL AERONAUTICS AND SPACE ADMINISTRATION GEORGE Co MARSHALL SPACE FLIGHT CENTER CONTRACT NO, NAS 8-20228 HUNTSVILLE, ALABAMA administered through: OFFICE OF RESEARCH ADMINISTRATION ANN ARBOR May 1967

This report was also a dissertation submitted by the first author in partial fulfillment of the requirements for the degree of Doctor of Philosophy in The University of Michigan, 1967.

TABLE OF CONTENTS Page LIST OF TABLES v LIST OF FIGURES vi NOMENCLATURE x ABSTRACT xiv CHAPTER I. INTRODUCTION 1 A. Purpose 1 B. Literature Survey 2 II. EXPERIMENTAL APPARATUS 10 A. Introduction 10 B. Drop Tower 11 C. Test Packages 18 D. Test Surfaces 23 E. Instrumentat ion 29 1. Recording Equipment 29 2. Pressure Transducer 30 35 Accelerometer 30 4. High-Speed Camera 32 III. TEST CONDITIONS 34 IV. TEST PROCEDURES 39 V. DATA REDUCTION 44 A. Time 44 B. Temperature 47 C, Pressure 48 D. Saturation Temperature 49 E. Acceleration 49 F. Heat Flux 51 G. Nusselt Number, Nu 59 Ho Modified Rayleigh Number, Ra' 59 I. Photographs 61

TABLE OF CONTENTS (Concluded) Page VI. RESULTS 63 A. General 63 B. Experimental Results 64 1. Film Boiling 64 2. Other Boiling Regimes 74 3. Photographic Results for Film Boiling 89 4. Anomalous Results 99 VII. DISCUSSION AND ANALYSIS 102 A. Film Boiling 1. Saturated Liquid Boiling Correlations 102 2. Subcooled Liquid Boiling Correlations 120 3. Boiling Film Thickness Analyses 123 B. Other Boiling Regimes 140 1. Minimum Heat Flux Boiling 140 2. Peak Heat Flux Boiling 146 3. Nucleate Boiling 151 4. Free Convection 155 VIII. SUMMARY AND CONCLUSIONS 157 APPENDIX A. REDUCED DATA AND SAMPLE PHOTOGRAPHS 160 1. Reduced Heat Transfer Data 160 2. Sample Photographs 181 3. Reduced Photographic Data 186 B. ANALYSIS OF THE FILM THICKNESS ON A FLAT PLATE HEATING DOWN 191 C. THE EFFECT OF AIR DRAG ON MEASURED (a/g) DURING FREE FALL 197 D. EVALUATION OF THE LUMPED ANALYSIS APPROXIMATION 200 E. ANALYSIS OF THE TEST PACKAGE-STEEL CABLE-COUNTERWEIGHT SYSTEM 214 BIBLIOGRAPHY 223 iv

LIST OF TABLES Table Page I. Summary of Test Conditions 38 II. Mean Vapor Film Thicknesses 99 III. Comparison of Analytical Predictions and Experimental Results for the Ratio (q/A)sc/(q/A)sat for a Vertical Disk at 3 and 5 Atmospheres 123

LIST OF FIGURES Figure Page 1o Drop tower facility. 12 2. Buffer assembly. 13 3. View of first test package and counterweight. 15 4. View of second test package and counterweight. 16 5, Second test package. 20 6. Pressure cover on second test package. 22 7o View of l-inch diameter sphere with stainless steel support rod, 24 8. Wiring schematic of 1-inch diameter sphere. 26 9. Disk for transient heat transfer measurements. 28 10. Sketch of test setup for obtaining high-speed motion pictures. 33 I.o Typical oscillographic record of temperatures within 1-inch diameter copper sphere with film boiling of liquid nitrogen. (a/g) = 1. 45 12. Typical oscillographic record during free fall with nucleate and transition boiling. (a/g) - 0. 46 13. Specific heat of copper. 52 14. Typical input to computer. 55 150 Typical output from computer. 56 16. Effects of geometry and orientation on saturated film boiling. 66 17. Effect of pressure on saturated film boiling. 67 1.8 Effect of subcooling on film boiling. 69 19o Effect of (a/g) on saturated film boiling on spheres. 70 vi

LIST OF FIGURES (Continued) Figure Page 20. Effect of (a/g) on saturated film boiling on disks. 73 21. Effects of pressure and subcooling on (qJA)min and transition boiling. 75 22. Effect of (a/g) on (q/A)min. 77 23. Effect of (a/g) on transition boiling at one atmosphere. 79 24. Effect of (a/g) on transition boiling at three atmospheres. 80 25. Effect of (a/g) on transition boiling at five atmospheres. 81 26. Effects of pressure, subcooling, and (a/g) on (/A)max. 84 27. Effects of pressure and subcooling on nucleate boiling. 86 28. Effect of (a/g) on saturated nucleate boiling. 87 29. Effect of pressure on free convection. 88 30. Composite tracings of photographs of film boiling on a sphere. 90 31. CompositeH tracings of photographs of film boiling on a vertical disk. 91 32. Composite tracings of photographs of film boiling on a horizontal disk heating up. 92 335 Composite tracings of photographs of film boiling on a horizontal disk heating down. 93 345 Anomalous film boiling. 100 35. Experimental ppol boiling data for nitrogen. 103 36. Correlation of saturated film boiling on spheres. 105 37. Correlation of saturated film boiling on spheres and cylinders. 107 38. Correlation of saturated film boiling on a disk. 109 vii

LIST OF FIGURES (Continued) Figure Page 39. Saturated film boiling correlation for a vertical disk. 112 40. Saturated film boiling correlation for a horizontal disk heating up. 113 4Lo Saturated film boiling correlation for a horizontal disk heating down. 114 420 Saturated film boiling correlation for flat plates. 115 43~ Effect of the exponent on (a/g) on a saturated film boiling correlation. e118 44. Saturated boiling correlations. 1,19 45. Subcooled film boiling correlation. 122 46. Dependence of film boiling heat flux on time. 130 47. Variation of heat flux and vapor film thickness with time. 131. 48. Film thickness and heat flux in saturated film boiling on a vertical disk. 133 49o Vapor film thickness in saturated film boiling on a horizontal disk heating up. 136 50 Vapor film thickness -variation in saturated film boiling on a horizontal disk heating down. 139 51. (q/A)min in saturated boiling. i42 52o (ATsat)min in saturated boiling. 1445 53~ Comparison of experimental and predicted (q/A)maxo 148 54~ Effect of subcooling on (q/A)max. 150 55. Effects of pressure and subcooling on nucleate boiling heat flux. 153 56 Heat flux with free convection, 156 viii

LIST OF FIGURES (Concluded) Figure Page A-1. Photographs of film boiling on a sphere. 182 A-2. Photographs of film boiling on a vertical disk. 183 A-3. Photographs of film boiling on a horizontal disk heating up. 184 A-4. Photographs of film boiling on a horizontal disk heating down. 185 B-1. Plate and disk configurations. 192 D-1. Flow sheet for digital computer program. 203 D-2. Digital computer program listing. 208 D-3. Computational procedure for digital computer program. 213 E-l. Sketch and free-body diagram of test package-steel cablecounterweight system. 215 E-2, The test package- steel cable- counterweight system as an idealized mass-spring-mass system. 218 E-3. Accelerometer records of (aB/g). 221 ix

NOMENCLATURE (Other nomenclature is defined as necessary) a Local acceleration A Area B Computational parameter-see Eq. (27) Bi Biot Number Cp Specific heat C Constants D Diameter E Parameter defined in Eq. (38) f Friction factor F Parameter defined in Eq. (39) F Vector force,etc. Force component g Acceleration due to standard (terrestrial) gravity go Mass-force conversion constant Gr Grashof Number h Enthalpy h Heat transfer coefficient hfg Latent heat of vaporization hIg Average enthalpy difference between vapor and liquid J Mechanical equivalent of heat k Thermal conductivity

NOMENCIATURE (Continued) ~ Average calculated drop thickness Q1 Length measured along z-coorindate L Length measured along x-coordinate Le Equivalent geometrical factor Lo Distance from leading edge to onset of turbulence iih Mass flow rate m Mass n Exponent n Outward-drawn normal to dA Nu Nusselt Number Nu" Doubly modified Nusselt Number —see Eq. (23) p Pressure, psia P Pressure, atm Pr Prandtl Number q Heat transfer rate r Radial coordinate Ra Rayleigh Number Rav Modified Rayleigh Number —see Eq. (14) Ra" Doubly modified Rayleigh Number-see Eq. (24) t Time T Temperature V Volume V Vector velocity xi

NOMENCLATURE (Continued) Vx,etc. Velocity component x,y,z Cartesian coordinates Y1,Y2 Local film thickness Ap Saturation pressure difference corresponding to heater surface superheat ATsat Heater surface superheat (Ts-Tsat) ca Thermal diffusivity a% Equivalent thermal diffusivity in heat conduction through a substance with change of phase ffi Thermal expansion coefficient Vapor film thickness 61 Variation in film thickness 6* Vapor film thickness at onset of turbulence-see Eq. (33) Dimensionless boundary layer thickness-see Eqo (31) Xc Critical wavelength kd Most dangerous wavelength Xt Viscosity p Density a Surface tension G Cylindrical coordinate xii

NOMENCLATURE (Concluded) Subscripts f Evaluated at film temperature I Liquid min Minimum max Maximum s Test object surface sat Evaluated at saturation conditions sc Subcooled sd Solid v vapor xiii

ABSTRACT Pool boiling of liquid nitrogen in a body force field less than standard gravity was studied using a transient calorimeter measurement techni.que. Experimental variables included: body forces from standard gravity to near-zero; a variety of geometries and orientationsof the boiling surface; subcooling from O0F to 30~F; pressures from 1 to 5 atmospheres; and boiling regimes from film to nucleate, plus free convection. Gravity was varied by using a drop tower and a counterweighted test package. In free fall, the test package achieved a level of less than 0.002 times standard gravity. Heat transfer surfaces included 1/4-, 1/2-, and 1-inch diameter spheres and a 3-inch di.ameter by 13/16-inch thick disk oriented vertically, horizontally heating up, and horizontally heating down. Subcooling was achieved by rapid pressurization of the liquid nitrogen; 3 and 5 atmospheres were used providing maximum subcooling of approximately 20~F and 300F. Results were obtained in the form of time vs. surface temperature, which were then expressed as heat flux vso the difference between the test surface temperature and saturated liquid temperature. These results are presented graphically. In addition, high-speed photographs were made showing the film boiling process. These photographs were used to determine vapor film thicknesses for the various geometries. All results were limited to the fiSm-boiling region except for those obtained with the 1-inch diameter sphere, which was used in all boiling regions~ In the film-boiling region, the heat flux on the spheres varied as diameter to the -1./8 power. The heat fl.ux on the d.isk, within the uncertainty of the measurements, did not exhibit any dependence on the disk orientation, but was approximately 100% higher than the heat flux observed on the spheres with similar liquid conditions~ The appearance of the vapor film on the disk as observed in the photographs differed with orientation. The heat fli.ux on the 1/2-inch and 1-inch spheres varied as the 1/3 power of acceleration. The heat flux on the 1/4-inch sphere and the disk varied as the 2/9 power of acceleration. For the 1-inch diameter sphere, the minimum and maximum heat fluxes were proportional to the 1./4 power of acceleration and were increased with subcooling and increased pressure. Nucleate boil.ing, within the uncertainty of the measurements, was not affected by variations in acceleration, pressure, or subcoolingo xiv

CHAPTER I INTRODUCTION A. PURPOSE Of the three modes of heat transfer, radiation, conduction, and convection, only convection is normally affected by a variable force field. In the past, this dependence was not usually significant. Within the last ten years, however, questions which previously had been primarily academic in nature began to have many practical applications in the new field of space technology. The possibility of vehicles being accelerated, in free fall or orbit, or subjected to other gravitational systems, made it desirable to have some reasonably reliable method of predicting how various physical phenomena would be modified under a varying force field. Because of the compactness possible, it may be anticipated that boiling heat transfer will continue as an important mechanism for power generation and energy dissipation for some time to come. Recently many different models have been proposed which purport to provide a correlation for boiling heat transfer data in the various boiling regimes, but none of them have been able to describe completely the various boiling processes. Most of the correlations include a dependence on the local gravitational field. While variations in the indicated dependence on (a/g) between different boiling regimes is not unexpected, the different predicted dependencies for a single regime appears to indicate shortcomings in at least some of the models. Use of particular correlations in space technology applications should there1

2 fore be attempted only after comparison with data which have been published on heat transfer with nonstandard force fields. The purpose of this investigation was to attempt to clarify some of the apparent discrepancies in the predicted dependence of heat flux on the gravitational field in the various boiling regimes. It was recognized that the size, shape, and orientation of the surface from which boiling was taking place could affect the results, so several different surfaces were used to obtain heat transfer data in the film boiling region. The effects of using subcooled and saturated liquid were investigated, and pressure on the boiling system was varied. A transient calorimeter measurement technique was used to study the range of effective gra'vity'from standard earth gravity to near-zero (free fall). Liquid nitrogen was used as the test fluid since it is inert and is convenient with the transient technique. B. LITERATURE SURVEY* Boiling heat transfer is characterized by the generation of vapor at a soLid-liquid interface due to heat transport from the solid to the liquid. The solid heat transfer surface is at a temperature above the liquid saturation temperature. The liquid bulk temperature is equal to or less than the liquid saturation temperature. The vapor may appear as individual bubbles, as a continuous film, or as a combination of both. Buoyant forces acting on the vapor tend to remove it from the hot surface in the form of bubbles of various shapes and sizes. After departure from the heat transfer surface, *Superscripts refer to References in the Bibliography.

3 the bubbles may collapse, coalesce with other bubbles, or move independently. Detailed examinations of the conditions under which these various behaviors are observed and descriptions of the various boiling regimes are presented in standard texts such as those of McAdamsl and Kreith.2 The level of boiling heat flux is affected by the rate at which the vapor is removed from the heat transfer surface. A change in the buoyancy force would be anticipated to affect the vapor removal rate, and therefore the heat flux, for a given heat transfer surface temperature. The effect may vary with the boiling regime. Analyses of the hydrodynamic aspects of nucleate and film boiling (e.g., Refs. 3-5) consider the liquid-vapor interface instability. For film boiling, Taylor instability is observed. The reduction or elimination of the gravity force will reduce or eliminate the liquid-vapor instability, significantly changing the mechanism of heat transfer. The consequences of this effect have been observed in this present work. Adelberg6 calculated the forces on a single bubble due to bubble dynamics, surface tension, drag, and gravity induced buoyancy. These calculations indicated that, for water, an effect of (a/g) on heat transfer might be expected only when (a/g) was larger than 50. Clark, et al7., evaluated the bubble Froude number (ratio of inertia to buoyant forces) in nucleate boiling for several liquids at 1 atmosphere pressure, (a/g) = 1, ATsat = 160F, and a bubble radius of 0.005 inch. Their evaluation indicated inertia forces were dominant for all liquids considered; for nitrogen, the bubble Froude number was 452.

Keshock, et al.,8 evaluated the forces on bubbles in nucleate boiling and found that'bubble departure diameter showed.a gravity dependence only for slowly growing bubbles; the inertial force controlled departure diameter for a rapidly growing bubble. Cochran, et al., evaluated the f rces acting on a bubble attached to a surface, and found that at'(a/g) - 1 and high subcooling (>100F) the principal removal forces were the pressure and dynamic forces, at low subcooling the principal removal forces were the pressure and buoyant forces, and at zero gravity the pressure and dynamic forces removed the bubbles at all subcoolings. Beckman and Merte10 obtained high-speed photographs of nucleate boiling of water at (a/g) from 1-100 and found that variations in acceleration affected the number of nucleating sites, the frequency of bubble departure, and, for values of (a/g)'between 1 and 3, the bubble departure size. Later growth period growth rates were also affected by variations in acceleration. The correlation proposed'by Rohsenowll for nucleate pool boiling, Eq. (58), predicts that (q/A) is proportional to (a/g)/2 (provided that the empirical constant, given as 2.97x105, is not a function of (a/g)). The equation developed'by Michenko12 for nucleate boiling, Eq. (59), predicts that (q/A) is proportional to (a/g)-2/3. Forster and Zuber13 and Forster and Greif14 predicted that (q/A) would be independent of (a/g). Frederkingl5 performed a combined kinematic and fluid dynamic analysis of a bubble column originating at a single site in saturated nucleate boiling. His results indicated that the heat flux at a single site was proportional to (a/g) /4, but did not consider the effect of (a/g) on the number of bubble sites.

5 Nucleate pool boiling experimental data have been reported for a wide range of (a/g). Merte and Clark16 using saturated water and (a/g) from 120 observed a change in (q/A) with (a/g) for a given ATsat. An increase in (q/A) was observed at low ATsat, but at higher ATsat, (q/A) decreased with increasing (a/g). Costello and Tuthilll17 observed a decreasing (q/A) with (a/g) increasing from 1 to 38 at a given ATsat, but did not present data at the low ATsat where Merte and Clark6 had observed a reversal of this trend. SherleyX8 reported a statistical increase of approximately 20% in (q/A) at a given ATsat when comparing (q/A) vs. ATsat data at (a/g) = 0 with similar data at (a/g) = 1. However, the variation of (q/A) for both levels of (a/g) was approximately +50%. Merte and Clark19 obtained (q/A) vs. ATsat saturated nucleate boiling data with liquid nitrogen at (a/g) = 1.0, o.6, 0.33, 0.2, and free fall (0.01-0.03). Their results. were consistent with those of Sherleyl8 in that no significant effect of (a/g) was observed in the nucleate boiling region. Numerous correlations have been proposed for predicting the maximum heat flux, (q/A)max (e.g., Refs. 20,21,22,23, and discussion of 3). They all predict (q/A)max is proportional to (a/g)1/4. Siegel24 suggests that this may be because they all use a horizontal infinite flat plate model. Costello and Tuthilll7 observed an (a/g)l/4 dependence of (q/A)max for 1 < (a/g)< 38 on a flat plate. Merte and Clarkl9 found an (a/g)1/4 dependence for (q/A)max with a 1-inch diameter sphere in the range 0 <(a/g)< 1. Usiskin and Siegel25 used a platinum wire 0.0453 inch in diameter to obtain (q/A)max data for (a/g) between 1 and free fall and commented that an

6 (a/g1/l4 variation appeared to provide a reasonable lower limit for their data. In an early work26 with nucleate boiling of Freon 114 from a horizontal platinum wire, it was observed that upon changing from (a/g) = 1 to free fall, that with no change in heat flux, the system changed to film boiling. Evidently the heat flux level was initially above that corrsponding to ((q/A)max for the free fall condition, and film boiling was the only possible condition. A range of ATsat over which (q/A)max would be expected to exist was predicted by Chang and Snyder.21 Merte and Clarkl9 observed an empirical constant in this equation had been derived for water. They modified the constant to apply to nitrogen and presented experimental results which fell within the predicted range. This prediction also included a dependence on (a/g) 1/4. Results for transition boiling with variations in (a/g) appear to'be limited to those of Merte and Clark19 for 0 <(a/g < 1. As discussed'by Siegel24 these data suggest that (q/A) as a function of ATsat in this region is insensitive to gravity reductions. Berenson3 predicted that the minimum heat flux with film boiling, (q/A)min5 on a horizontal flat plate was proportional to (a/g)1/4. He also obtained an expression for ATsat at which (q/A)min would occur. This ATsat was proportional to (a/g)-1/6. The measurements of Merte and Clarkl9 for a 1-inch diameter sphere agreed closely with the predicted (q/A)min, but the value of ATsat at this condition did not.

7 Analyses of the film-boiling region have been performed using several different models. Bromley27 analyzed film boiling from a horizontal tube with viscous flow around the tube to the top. The equation he obtained is given as Eq. (20) and predicts (q/A) varies as (a/g)1/4. Adelberg6 performed a similar analysis for a horizontal tube and also predicted that (q/A) would vary as (a/g)1/4. Berenson5 analyzed film boiling from a horizontal flat plate with a thin film of uniform thickness on which cylindrical bubbles with hemisperical caps were superimposed at regular intervals. The equation he developed is given as Eq. (26), and predicts (q/A) varies as (a/g)3/8. Hamill and Baumeister28 performed an analysis of film boiling based on a cellular model and obtained an optimum cell diameter (wavelength) which was intermediate between Xc and Xd (see Eqs. (21) and (22)). The expression they obtained for film boiling was h = 0.410 ( /8 (1) vo Vfhffg(PrPVf) 1/28 wevfATsat p g(pR-Pvf) where h hfg 1 + 19 CQpATsat (2) fg fg 20 hfg which they observed agrees with the equation of Berenson (Eq. (26)) within 4%. Equation (1) predicts (q/A) is proportional to (a/g)3/8. Baumeister, et alq,29 considering film boiling to water drops on a flat plate, developed an equation for the heat transfer from the plate as

8 h = 0.68 h (3) ATsatIlvfLe J where Le = 2 (4) Equation (3) predicts that (q/A) is proportional to (a/g)l/4 The model used to obtain Eq. (3) assumes that the generated vapor moves parallel to the flat plate, rather than normal to it as with the other flat plate models. An analysis of film boiling on a vertical surface was performed by Hsu and Westwater.30 They predicted that in the laminar film region (q/A) would be proportional to (a/g)l/4,'but in the turbulent film region the exponent on (a/g) would be between 1/3 and 1/2. Frederking and Clark31 analyzed film boiling on a sphere at(a/g)= 1 and predicted that (q/A) would be proportional to (a/g)1/3. Siegel24 commented that the relation proposed by Frederking and Clark (Eq. (16)) contained contributions from both the laminar and turbulent regimes. Results obtained for film boiling on a 1-inch diameter sphere for 0 <(a/g)< 1 by Clark and Merte (Refs. 7, 19, 32, and 33) show (q/A) to be proportional to (a/g)1/3. Pomerantz34 obtained film boiling results on a 0.188-inch diameter horizontal cylinder at 1 <(a/g)< 10, and found (q/A) was proportional to (a/g)0'336. Heath and Costello35 obtained results for film boiling of ethanol, pentane, and Freon 113 on horizontal and vertical flat plates, for 1 < ~/g)< 21 in a centrifuge. Their plates were 6 inches long and 1 or 1-1/2 inches wide. Their results were adequately predicted by

Berenson's correlation (Eq. (26)-(q./A) proportional to (a/g)1/4) when it was modified by a width correction factor. Heath and Costello35 did not find any significant difference in film boiling heat transfer characteristics between the horizontal and the vertical plate orientation, although Class, et al..36 using a plate 22 inches long and 1 inch wide in liquid hydrogen, observed heat fluxes as much as 25% higher on a vertical plate than were observed ona horizontal plate heating up.

CHAPTER II EXPERIMENTAL APPARATUS A. INTRODUCTION The primary object of this investigation was to determine the effects on boiling heat transfer of varying the gravitational field in the range O <(a/g)< 1, with additional variables of test surface geometry, bulk liquid subcooling, and pressure. The most simple way of approaching (a/g) = 0 with an experimental package was with the use of a drop tower (alternative techniques include using an aircraft flying a parabolic trajectory or a satellite in earth orbit). This permits continuous direct measurements during free fall. The use of a counterweighted system added the desired capability for obtaining intermediate values of (a/g). (A discussion of the relationship between free fall, counterweighted drop, and various values of the gravitational field, is presented in Appendix E.) The use of a drop tower required a means of'bringing the test package to rest, as well as a means of recording data obtained while the package was falling. A test facility with these capabilities was designed and built in the Heat Transfer Laboratory of the Department of Mechanical Engineering. A drop tower provides relatively short test times, of the order of a few seconds for realistic heights, so that steady-state heat transfer measurements are not practical. A transient technique, using a test surface as a dynamic calorimeter, permitted an accurate determination of heat flux when 10

11 the test surface physical characteristics and the variation of temperature with time were known (see Section V.F). The use of various test surfaces permitted the effects on film boiling of variations in geometry and test surface orientation, in combination with variations in (a/g), to be evaluated. The test fluid used was liquid nitrogen, generally at atmospheric pressure and saturated. In order to investigate the effects of subcooling on boiling, subcooling was achieved by rapid pressurization of the liquid nitrogen with helium just prior to the test (in preference to supplying a cooling system to maintain a subcooled bulk liquid nitrogen temperature level). This also provided the capability for varying the pressure on the boiling liquid. A subsequent need for photographic information on the boiling phenomena with different test surface geometries in the film-boiling regime at (a/g) = 1 necessitated the acquisition of a highspeed motion picture camera. B. DROP TOWER The drop tower location in the Heat Transfer Laboratory permitted a total drop distance of 31 feet, which provided approximately 1l4 seconds of test time in free fall. A sketch of the drop tower facility is shown in Fig. 1. The hydraulic buffer arresting gear shown in Fig. 2 is basically a 6inch diameter hydraulic piston with programmed orifices designed specifically for this application. The buffer is capable of decelerating a 150pound mass from 45 feet per second to rest in a distance of 2-1/2 feet with a maximum measured value of (a/g)o30.

12 RELEASE MECHANISM. ROOF' TEST PACKAGE WORKING PLATFORM SECOND FLOOR THERMOCOUPLE (SHIELDED) CABLE 31' COUNTERWEIGHT CABLE FIRST FLOOR COUNTERWEIGHT BASEMENT —--- HYDRAULIC BUFFER ARRESTING GEAR Fig. 1. Drop tower facility.

13 RUBBER PAD ENSOLITE PAD |"0 AUTOMOBILE SPRING "Up" Position 6 HYDRAULIC PISTON BRONZE BEARINGS 2." "Down" Position., — CYLINDER WITHI PROGRAMMED ORIFICES HYDRAULIC FLUID Fig. 2. Buffer assembly.

14 The use of an automotive-type coil spring, four inches of Ensolite energy-absorbing synthetic rubber compound, and one inch of heavy rubber padding on the top of the piston helped to reduce the initial acceleration of the piston while decreasing the initial deceleration of the test package, Two different test packages, described in more detail in Section II.C, were utilized. The first package (Fig. 3) was used for obtaining saturated data at one atmosphere pressure, and weighed approximately 120 pounds. The second test package (Fig. 4), which could be pressurized to 100 psia, was used for obtaining both saturated and subcooled data at pressures of from 1 to 5 atmospheres, and weighed approximately 135 pounds. The counterweight used to provide intermediate values of (a/g) between 0 and 1 (Figs. 3 and 4) was made from a piece of aluminum tubing 6 inches in outside diameter and 5 feet long, and. included a provision for varying its weight by adding or removing quantities of lead shot. The empty weight of the counterweight was 11 pounds, 5 ounces, which permitted minimum experimentally measured values of (a/g) of 0.20 to be obtained with the first test package and 0.17 to be obtained with the second test package. The counterweight was decelerated at the end of the drop by two Firestone Rubber Company automotive-type air springs and was guided by two vertical wires which limited its horizontal motion. Initially the test package was supported by the counterweight cable, and the counterweight was held down by a solenoid-operated latch. It was observed that when the counterweight was released the test package and the

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17 counterweight in combination with the cable connecting them behaved as a spring-mass system with a resultant sinusoidal variation in the measured value of (a/g). This variation in (a/g), discussed further in Appendix E, was reduced by supporting and releasing the test package directly, so that the cable initially supported the counterweight, rather than the test package. The test package was raised from the buffer to the release position by means of an electrically driven hoist, which was also used to reposition the buffer piston in the "up" position. Two flexible shielded cables carried all of the instrumentation leads from the test package to a control panel located on the second floor. From the control panel the wiring led to the appropriate recording equipment, reference junctions, or calibration equipment. These two cables were attached symmetrically to the test package to balance any overturning moments, and had no measurable effect on the values of (a/g). The first test package was supported by a short length of 17-gauge resistance wire prior to a test. The package was released by passing a large current through the wire, heating it very rapidly. The strength of the wire decreased with increasing temperature until the wire failed, providing a torque-free release. An indication of the current was superimposed on a time record (see Section II.E), and the cessation of current indication identified the release time. The wire normally parted approximately 1,3 seconds after the current was initiated. The second test package was supported by a stud which engaged a solenoid

operated latch. The current which activated the solenoid also provided an indication of the time of release on the recorder. This system permitted better control of the time at which the test package was dropped. C. TEST PACKAGES The first test package provided for fractional gravity and free-fall testing using liquid nitrogen at saturated 1 atmosphere conditions. It consisted of a simple framework to which a 3-liter stainless steel beaker, insulated on the sides and bottom with 3 inches of Styrofoam, was attached (see Fig. 3). A lid on the beaker reduced convection currents over the nitrogen, and thus the evaporation rate, as well as potential oxygen contamination from the atmosphere. Provision was made for positively positioning any test surface which was used, so that repeatability was ensured. The test surface was manually placed in the test fluid at the start of each test. Four guide wires were provided, one at each corner of the framework. These guide wires kept the package from twisting while it was being raised to or in the release position, aligned with the rectangular openings it passed through while dropping, and supported in an upright position on the buffer piston after completion of a drop. The first package was found to reach a minimum value of (a/g) which varied from.01 to.03. Part of this departure from zero (a/g) during free fall was attributed to guide-wire drag, which varied from run to run and even during different portions of a run. The remainder was attributed to air drag, which is analyzed in more detail in Appendix C.

19 The second test package provided a capability for rapidly pressurizing the test fluid up to 100 psia and for shielding the test fluid container from the external air flow. Pressurization permitted both the system pressure and the test fluid subcooling to be varied, while the air flow shielding permitted a more nearly constant value of (a/g), much closer to zero, to be maintained during free fall. There are two major components of the second test package: an outer package which serves as a pressure vessel, windshield, and mounting structure for fastenings and some instrumentation; and an inner package which contains the test fluid test surface, and additional instrumentation. A sketch of this test package is presented in Fig. 5. The. inner package consists of a 3-liter stainless steel beaker wrapped in fiberglass mat and tinfoil insulationand a mounting plate. A hinged test surface support is located on the mounting plate, and provides positive positioning of the test surface for all tests. A solenoid operated release permits the test surface to be placed in the test fluid from a remote location with the outer package sealed and pressurized. Support chains which position the inner package prior to a free-fall test are also attached to the mounting plate. The outer package is a 14-inch diameter cylinder 36 inches long, blunted on the lower end and flat on the upper end. It provided a minimum of 1-inch radial clearance between the inner and outer packages and also between the outer package and the sides of the drop tower, and a 6-inch vertical clearance for the suspended inner package.

20 COUNTERWEIGHT CABLE RELEASE STUD (WHEN USED) CBLE PRESSURE RELIEF VALVE QUICK DISCONNECT PRESSURE. PRESSURE FITTING TRANSDUCER FRICTIONAL RELEASE FOR INNER VESSEL OUTER PACKAGE SUPPORT CHAINS SOLENOID TEST SURFACE SUPPORT RELEASE FOR TEST OBJECT MOUNTING PLATE LIQUID THERMOCOUPLE TEST OBJECT LIQUID NITROGEN INNER PACKAGE INSULATION CUSHION MATERIAL LEAD BALLAST Fig. 5. Second test package.

21 The initial weight of the combined inner and outer package was approximately 75 pounds, which was too low to provide acceptable initial impact behavior with the buffer system. No further modifications were practical with the existing buffer system, so sufficient ballast was added to the outer package to bring the total weight up to approximately 135 pounds. The removable cover of the outer package was made in two sections. One section provided access to the interior of the package, and the other section provided a mounting location for fittings, connections, and instrumentation. Pressure was controlled through a quick-disconnect pressure fitting and a pressure relief valve, and monitored with a strain gauge type pressure transducer. A view of the cover showing the pressurizing hose attached to the quick-disconnect fitting is shown in Fig. 6. For fractional gravity tests, the inner package is placed on thecushion material in the bottom of the outer package. This cushioning serves to reduce the impact felt by the inner package when the outer package first contacts the buffer. For free-fall tests the inner package is positioned midway between the top and bottom of the outer package by means of the support chains. The upper ends of these chains are fastened to the bottom of a T-shaped bar which in turn rests on a spring-loaded friction catch. When the outer package is dropped, the force between the T-bar and the catch goes to zero, and the spring retracts the catch. This allows the inner package to float freely within the outer package.

22 B:'' -'#.', -, #.,',. 02g''.g', i,;:g i; -E iiS'.....:.................',......................'........'.'..'..g:'; -'' 2';,'22'i2',;"'#'22'' ~ ~................~i........EEE -i-gg E'2 z'., 2,''' 22".2'.S.:::5:;:':,'i,'l l:;i.':E:':', -#-::!:..- i':; i0;i.::'.:S.............-.'...........''- "''gS''.:,::B'': BEB.:'#'::E:E:-:::-:::::':.::E:E':;.::E::E:E:::::::-::........:...:::;:::.-:::-:';:-:..:::.........:E-:.:E.:::E a~~~~~~~~~~~~~~~~~~.................. |~~ ~~~~~~~~~~~~~~~~~~~................... ~~~~~~~~~.........._..... E....... -........||..........................................................l............. __...... __~~~~~~~~~~~~~~~~~~~~~~~~~~..........i_ I* _.1.i.............................................. l 0 ~~~~~~~~~~~~~~~~~~~~~~~............ _...................................... L~~ l~ ~ ~ _:.:........, 1.................................. 1..._........ - 8 8' —------— i, u: - g g g g::g::g:::: —:::-g:: g::: g::.2* g:-:.................::::-:s E:a - E; E -4@ E:: i: B.:: i i i -:E::::E::: -:::::- E::::::>::.::::: -:::E-:: s:.'E.i:::E 2:.-.::..::.S...:.::.:S.S.....:::::. S _-:-::::-::-E:.:S.-::..E.::;: i::.:::::::E:Ei:E::::..:::.:::-:-.:::::-E:-E:.:..E:::E::i.::i4>::;:-::...-......::..-:'42x* i: ER.:'i E S::E:-:RE"R-:'E:: EEE:::::E'i::'iE:. E:: R- E:i':i::EE:'ii'-:-:; b E E:E:-: E - LC —... —. —-..........................: i i::-E; E-:R:''SER''!E' i!. E i:,-i'E.'E iR:E!:, i:: E:!E-'::'i: E i.:.# -E E...'..':...'. I - - E' E..::.:::::-:':::E:::,i:E::i: E::-::::-::...;:.::::::,..;:-.::':::E: i...... E::.-,:: -::........'...:: -:::< -::i: -...:E.E'.:.',"iE#EE'!:E! iE l'SE,'i".E,::EE"ER.,:!EEERSE; i!:':E!! iE!-;E'E.:::E!EE iEE-E.......................;EE, i iE::.'.''-E:!E g'lE-i'EE!S.ES......................;"''E EE"'!''''! E!: SEgE:S: l SSE:E'EX!'" ~i CE E' -....B,:.''.'. —''""'''''''''~ ~~~~~~~~~~~~~~~~~~~...............! g. g::.g.....-; i..... i....... x x;B -g l gg g i: g:-; l gi i ii:i:i: i:: Fig. 6. Pressure cover on second test package.~~~~~~~~~~~~............

23 The position of the inner package relative to the outer package was monitored during several drops, and it was observed that the inner package moved up about one inch during the drop. This was attributed to an initial upward impetus supplied by the elastic energy in the support chains as the load decreased to zero. The relative motion downward which was anticipated due to increasing air drag did not become large enough to overcome this initial upward motion during the 1.4 seconds of free fall which were available. This relative motion had no effect on the measured value of (a/g). D. TEST SURFACES Previous work by Merte, et al.,19 had established the feasibility of using a 1-inch diameter copper sphere as a dynamic calorimeter in boiling liquid nitrogen at one atmosphere. This was chosen as the first test surface here for its inherent symmetry. In order to determine whether there were any size effects with a sphere, 1/2-inch and 1/4-inch diameter copper spheres were also tested. Although a limited amount of testing at one atmosphere was performed with the 1/2-inch diameter sphere, most of the sphere tests were performed with the 1-inch and 1/4-inch diameter spheres. The 1-inch and 1/2-inch diameter spheres were supported on 1/16-inch diameter stainless steel rods (see Fig. 7), and the 1/4-inch diameter sphere was supported by its thermocouple wires. The 1-inch diameter sphere had three thermocouple holes drilled into it. One was used for a direct measuring junction at the upper surface, one for a differential thermocouple 900 along the surface from the direct measuring junction, and one for a dif

24 Fig. 7. View of 1-inch diameter sphere with stainless steel support rod.

25 ferential thermocouple at the center of the sphere. The differential thermocouples used the copper in the test object as the intermediate conductor between the junctions, and so were fabricated of a single 30-gauge constantan wire held in place by a drop of soft solder. They were used only to verify the accuracy of the lumped approximation or to indicate the surface-to-center differential temperature when a distributed analysis was necessary. The wiring schematic for the 1-inch diameter sphere is shown in Fig. 8. The 1/2-inch and 1/4-inch diameter spheres were provided with single direct measuring junctions only, and were otherwise similar to the 1-inch diameter sphere. The thermocouples used consisted of 30-gauge copper and constantan wires spark welded together and fastened to the bottoms of the drilled thermocouple holes with soft solder. A piece of polyethylene tubing was slid over each pair of thermocouple leads down to the bottom of the drilled holes. The tubing extended a short distance from the sphere surface, where individual pieces of tubing were placed around each wire. The thermocouple holes were sealed with Glyptal, as were the plastic sleeve joints. The tubing served to prevent heat conduction from the thermocouple junctions to the liquid nitrogen through the wire itself, and to provide extra strength in the region where thermocouple wire breakage was most probable. Much of the experimental data and analyses presented in the literature for boiling heat transfer apply to flat surfaces. To determine what geometrical effects, if any, existed in conjunction with reduced gravity, a disk 3 inches in diameter and 13/16 inch thick was fabricated. The diameter was

CONNECTIONS MADE THROUGH COPPER OF TEST OBJECT ITSELF SOLDER I - -- I I I I 1/~J2" 1/16 stainless steel- i I LEAD - - - I I I li.I I I TL Fig. Wiring schematic of 1-inch diameter sphere - I T,,,i I I i 1/16" Stainless Steel!! I Supporting Rod j I I'I i \ \ ____I COPPER WIRE \k _ I CONSTANTAN WIRE T, Fig. 8. Wiring schematic of 1-inch diameter sphere.

27 as large as could be fitted into the 5-liter beaker while preserving sufficient clearance between the test surface and the beaker to prevent the presence of the beaker from affecting the boiling from the disk. The thickness was a compromise between the desired total heat capacity and the undesired temperature differentials within the disk. The disk could be positioned in any orientation, so that possible differences in heat transfer characteristics between horizontally oriented and vertically oriented flat plates could be investigated. Electrolytic tough pitch copper was chosen as the material for all test surfaces because its properties were well documented down to temperatures below that of saturated liquid nitrogen at one atmosphere. Because of the relatively high thermal conductivity of copper, it was possible to treat the entire test objects as lumped systems in the film-boiling region. In other boiling regimes it was necessary to consider each test object individually to determine whether the lumped approximation was acceptable (see Appendix D). It was originally intended that radial thermal isolation be provided for the disk test surface by machining several narrow, deep concentric grooves in the underside of the test surface. The machining properties of the electrolytic tough pitch copper made this impossible with the available machine tools, so an alternate gridwork pattern was chosen, as shown in Fig. 9. This figure shows only the test surface portion of the disk; a disk of similar size and construction is attached to the backside to provide a plane of symmetry and to prevent the liquid nitrogen from contacting the

28 Outlet for Thermocouple Wires ot ~ 1.062 T yp. Junctions Fig. 9. Disk for transient heat transfer measurements.

29 thermocouple junctions directly. A small gap at the center plane further isolates the two disks. Five thermocouple locations were provided as indicated. One was a direct-measuring junction located at the center of the test surface. The other four were differential thermocouples located as shown in Fig. 9. The differential thermocouples were used only to verify the validity of the lumped approximation in the film-boiling region. Copper and constantan thermocouples, spark welded together and fastened in place with soft solder, were used. The disk was supported at two places on the periphery by stainless steel straps. Any desired test surface orientation (e.g., horizontal heating up, horizontal heating down, or vertical) could be achieved by using the appropriate straps. E. INSTRUMENTATION 1. Recording Equipment A Sanborn Model 150 four-channel recorder was used for recording thermocouple, accelerometer, and pressure transducer outputs. This recorder has interchangeable preamplifiers so that low-level preamplifiers, AC-DC preamplifiers, or DC coupling preamplifiers could be used depending on the recording requirements. All of these preamplifiers are equipped with zero supression. The maximum sensitivity possible with the low-level preamplifiers used for thermocouple output recording was 10 pv/mm. At liquid nitrogen temperatures one mm corresponds to approximately 10F when operating with maximum sensitivity.

30 To minimize the influence of possible drift in the recording system during a test, it was calibrated against a Leeds and Northrup 8662 potentiometer immediately before and after every test. The four channels were normally used for recording test surface temperature, pressure in the outer test package, and two test fluid temperatures. The test fluid bulk temperatures were measured at two different levels to verify that the fluid was at a uniform temperature throughout, and also that the test fluid free surface was at least 1 inch above the top of the test object. The Sanborn recorder also has provisions for placing a timing mark on the record and this provided the time base for data reduction. Other signals indicating events such as duration of current flow (see Fig. 12) or solenoid operation can be superimposed on this timing record (see bottom trace, Fig. 12). 2. Pressure Transducer A strain-gauge type force transducer was used to measure pressure within the outer package. A dial face pressure gauge was calibrated to within ~0.2 psi using a dead weight tester, and the pressure transducer was then calibrated against the pressure gauge. The nominal operating range of the transducer is 0-100 psig. 3. Accelerometer A Kistler Model 303 Servo-Accelerometer was used to monitor the package accelerations under both fractional gravity and free fall. The output from the accelerometer was a voltage which was recorded on the Sanborn re

31 corder with the pressure and temperature records. The accelerometer was not used on every test but only on a series of acceleration tests which were used to verify the gravity levels for each of the counterweight masses tested. The maximum resolution achieva'ble in measuring (a/g) with the accelerometer in the range of zero gravity was of the order of ~0.001. This limitation was imposed by the noise level in the recording system including any sixty-cycle pickup. Calibration of the accelerometer was achieved by means of a special calibration fixture constructed specifically for this purpose. The calibration fixture permitted accurate and repeatable positioning of the accelerometer over all relative positions of the measuring axis of the accelerometer and the normal gravity vector. Thus (a/g) imposed on the accelerometer could be varied from +1 to -1. A zero value of (a/g) was imposed by placing the accelerometer at 900 to the normal gravity vector. The voltage output from the accelerometer under calibration conditions varied from +5. to -5. volts DC. In order to avoid potential damage to the galvanometer in the Sanborn due to excessive voltage inputs when operating at maximum sensitivity, a set of limiting diodes was installed in the system. These limited the voltage which the Sanborn could see to a level which would not overload the galvanometer. It was possible to change the level at which these limiting diodes acted so they could be used at the various fractional gravity levels (where the galvanometer was operating at reduced sensitivity) as well as at free-fall conditions.

32 4. High-Speed Camera Many photographic studies have been made of the boiling phenomenon, but most of these are studies of boiling from horizontal or vertical plates or wires. In order to aid in the understanding of boiling on a horizontal plate heating down and on a sphere, some additional photographic coverage was indicated. A high-speed framing camera (Dynafax Model 326) manufactured by the Beckman and Whitley Company was utilized to obtain photographs of the boiling process at (a/g) = 1. This camera has a continuously variable framing rate ranging from 200 to 26,000 frames per second; a nominal value of 1000 frames per second was found to provide the best results for this application and was used for all the data presented here. A maximum of 224 frames could be obtained on one film strip. A sketch of the test setup utilized is shown in Fig. 10. The water and flat glass around the dewar eliminated most of the view distortion caused by diffraction and substantially reduced radiant heating of the liquid nitrogen by the high intensity lights. The black felt provided good photographic contrast for the test objects. The exposures appeared as two parallel sequences with 16 mm film spacing on a single strip of 35 mm film. After developing, the film was slit and spliced to provide one strip of film suitable for use in a standard 16 mm projector. It was thus possible to examine the film-boiling phenomena both on a frame-by-frame basis and by continuous projection.

33 Black Felt Liquid Nitrogen and Background Test Object Unsilvered (Transparent) Glass Dewar Water Flat Glass High Intensity Lights High Speed Motion Picture Camera Fig. 10. Sketch of test setup for obtaining high-speed motion pictures.

CHAPTER III TEST CONDITIONS Liquid nitrogen was used as the test fluid for this investigation because it is an inexpensive, readily available, easy to handle cryogenic liquid with well known physical properties. It was stored in a dewar at one atmosphere saturation conditions (-321.20F at 14.7 psia). The effects on boiling heat transfer of varying (a/g) between 0 and 1 have been reported by Merte, et al.19 for the 1-inch diameter sphere with saturated liquid nitrogen at one atmosphere using the first test package. Values of (a/g) of 1.0, o.6, 0.33, 0.2, and free fall (for these tests, free fall corresponded to O.01 <(a/g)< 0.03) were used. A predictable change in heat transfer rates at a given ATsat was observed to occur for (a/g) between 0.2 and 1.0. Therefore, only one value of (a/g) between 0 and 1 was chosen for the present investigation. The value chosen was obtained'by using the empty counterweight, and was found to vary with both the test package and the test object. The experimentally measured values were: with the first test package and a spherical test surface, (a/g) 0.20; with the second test package and a spherical test surface, (a/g) = 0.17; with the second test package and a flat test surface (disk), (a/g) = 0.16. These variations occurred because of the differences in weights of the two test packages and of the different test objects. The free-fall tests performed using the second test package provided measured levels of (a/g) of 0.001~0.001. 34

35 In order to perform tests using subcooled liquid, it was necessary to raise the saturation temperature of the nitrogen without raising the bulk temperature. This was accomplished by pressurizing the second test package. After pressure testing the second test package to 100 psig, it was decided to limit test pressures to 60 psig, or 5 atmospheres absolute. This provided a maximum subcooling of approximately 32~F. An intermediate value of 30 psig, or 3 atmospheres absolute, provided a maximum subcooling of approximately 20OF. In practice, considerable deviation from these maximum values was observed. The bulk temperature of the liquid nitrogen was monitored at two different locations during each test, and it was found that the liquid frequently increased in temperature a few degrees'between the time that pressurization was completed and the time that the test was actually run. Some of the reasons for this are the convective heat transfer between the relatively warm gas in the test package and the liquid nitrogen, and the fact that when the test object is placed into the liquid nitrogen, the vapor created at the surface of the test object recondenses into the bulk liquid, with a corresponding addition of heat to this liquid. When the test object was the 1-inch or 1/4-inch diameter sphere, the liquid was within a few degrees of the nominal maximum possible subcooling. With the disk, because of its larger thermal mass, some nominally subcooled tests were made with the liquid nitrogen within a few degrees of saturation temperature, and saturated liquid temperature measurements indicated significant amounts of superheat in a few cases. The degree of subcooling was approximately constant during a test run with the exception of the full temperature range

36 (a/g) = 1 data where, particularly in the case of the disk, as much as 18~ variation in indicated subcooling was observed. The exact subcooling, or range of subcooling, for each test is included in Appendix A. Nominal values of 15~F at 3 atmospheres and 250F at 5 atmospheres were observed for most tests. To determine which observed changes in boiling characteristics were due solely to subcooling effects and which were due to pressure variation, all subcooled tests were repeated at the same pressures under saturated conditions. When gaseous nitrogen was used to flush out the test package and pressurize the liquid nitrogen, it reached equilibrium at the new saturation conditions in approximately 5 minutes, aided by condensation of the pressurizing gas. When the vessel was first flushed and then pressurized with gaseous helium, the liquid temperature increased very slowly toward the new equilibrium point, so that saturation conditions were not reached for almost 30 minutes. Consequently, helium gas was used as the pressurizing medium for all subcooled boiling tests, and nitrogen gas was used as the pressurizing medium for all saturated boiling tests at elevated pressures. Six different test surfaces were employed during the testing: the 1inch, 1/2-inch, and 1/4-inch diameter spheres, and the 3-inch diameter disk in the vertical, horizontal heating up, and horizontal heating down positions. All of the available combinations of (a/g), subcooling, and pressure were not used with every test object. The conditions under which heat transfer data were obtained for the various test surfaces are summarized in

37 Table I. For the disk, only film boiling data are reported, although a few runs were made in the nucleate boiling region. The difference between the first test package and the second test package is significant only for free fall, where a large difference in the measured values of (a/g) exists. The high-speed photographs which were obtained of the boiling phenomena were limited to one atmosphere saturated conditions at (a/g) = 1 using liquid nitrogen. The photographs were taken because of questions which arose after examination of the film-boiling heat transfer results with the disk, so the disk was photographed in the vertical, horizontal heating up, and horizontal heating down positions. The 1-inch diameter sphere was photographed to provide film boiling coverage for another geometry for comparison purposes. Separate sequences were obtained for each test surface at values of ATsat of 1000F, 2000F, and 3000F.

TABLE I SUMMARY OF TEST CONDITIONS Test P, atm: 1, Saturated 3, Saturated 3, Subcooled 5, Saturated 5, Subcooled Object a/g: 1.0 0.6 0.33 0 1.0 0.2* 0 1.0 0.2* 0 1.0 0.2* 0 1.0 0.2* 0 1-inch sphere x2 xi xl x2 x x x x x x x x x x x x 1/2-inch i 1 sphere x x 1/4-inch sphere x x x x x x X X x x x x x x x Disk, heating up Y Y Y Y Y Y Y Y Y Disk, heating down y y y y y y y y y Disk vertical Y Y Y Y Y Y Y Y Y Y Y Y Y Y Y Note: Data obtained using second test package except as indicated: x - includes some data in the transition, peak and/or nucleate boiling region as well as film bailing data y - film boiling data only *a/g value of 0.2 includes data at 0.16 and 0.17 as well. 1Data taken with first test package. Data taken with both first test package and second test package.

CHAPTER IV TEST PROCEDURES One test or test run includes all of the operations necessary to obtain one time vs. temperature record for a test surface which has been immersed in liquid nitrogen. A standardized test procedure was prepared with appropriate modifications to satisfy individual test requirements. Operations common to all tests included cleaning and preparation of the test surface, instrumentation calibration, and test surface immersion. Tests under fractional gravity required the use of the counterweight system with the inner test package attached to the outer vessel. In the free-fall tests the inner test package is suspended within the outer vessel prior to being dropped. Pressurized tests required flushing and pressurizing of the outer vessel. At the beginning of each day's testing, the test surface was cleaned using copper polish to remove any tarnish or other corrosion. Additional treatment was limited to careful washing of the test surface with reagent grade acetone prior to each test to remove any contamination deposited by handling. At completion of a test the test object was at liquid nitrogen temperature and had to be heated to room temperature before another test could be made. A jet of high-pressure line air was directed on the surface of the test object to hasten this heating. The 1/4-inch diameter sphere did not require this assistance to return it to room temperature rapidly. A Leeds and Northrup 8662 potentiometer, which was calibrated against an internal standard cell every hour during testing, was used to supply a 39

40 voltage source for calibration of the instrumentation. A resistor in each circuit used for thermocouple calibrations was adjusted to duplicate the resistance of the thermocouple wires, so that the voltage drop from the 8662 potentiometer was matched to that from the thermocouple. This calibration procedure was performed immediately before and immediately after every test for every thermocouple being used. Normally the calibrations were consistent; when they were not, the average of the two calibrations at each increment of voltage was used if the changes were minor, or the test was discarded. The pressure transducer provided a linear voltage-pressure relationship over its operating range, so standard settings on the Sanborn recorder were used to provide the required calibrations for each run. Pressure was also calibrated immediately before and immediately after each run. The accelerometer was calibrated using the calibration fixture as described in Chapter II. It was necessary to include a voltage limiting diode circuit in the output from the accelerometer. If the voltage to the Sanborn recorder were not limited, the internal galvanometer would be subjected to excessive current flow at (a/g) = 1 and upon impact with the recorder set at the desired sensitivity level to monitor the fractional gravity or free fall. Potential damage to the pen or the galvanometer windings was prevented by use of the voltage-limiting circuit. The accelerometer was used only on dummy runs (no other instrumentation functioning, although physical similitude was maintained) to establish the value of (a/g) for each particular combination of test package, test object, and (if used) counterweight. All four channels of the Sanborn recorder were

41 required for other variables (three temperatures one pressure) during the test runs. Time reference was supplied by a pen deflection which occurred every 60 cycles of line current. The recorder strip chart velocity was assumed to be constant between pen deflections as long as the deflections were equally spaced (this was the case except for a starting transient when the chart drive was initially engaged). Preparation for a test was initiated by filling the stainless steel beaker with liquid nitrogen from a portable 25-liter dewar. The test surface was cleaned with reagent grade acetone, and placed in position for immersion in the nitrogen. For a free-fall test, the inner package was suspended from the spring-loaded pawl attached to the outer test package. For a fractional gravity test, the inner package was placed on the bottom of the outer test package. The thermocouples and the pressure transducer were calibrated. The pressure relief valve was placed in the open position and the cover on the outer package was bolted down. The test package was raised to its release position using the hoist, and the release stud was engaged in the solenoid operated release mechanism. The hoist cable was detached and the package was ready for either pressurization or immersion of the test object. The liquid nitrogen was initially at one atmosphere saturated conditions. For elevated pressure saturated tests, dry gaseous nitrogen was used as the pressurizing medium. The pressure was monitored and maintained within ~1 psi of the desired pressure until the liquid temperature (also monitored) stabilized at saturation. Saturation conditions were verified

by comparing the actual and tabulated saturation temperatures for the desired pressure, and by observing that a small change in test package pressure was accompanied by a small change in liquid temperature. The system was then ready for immersion of the test object. For subcooled tests, dry gaseous helium was used as the pressurizing medium. As soon as the desired pressure was reached, the system was ready for immersion of the test object. The test object was then immersed in the liquid nitrogen. For the pressurized tests, the pressure was continuously monitored and maintained at the desired level +1 psi. Shortly before the anticipated drop time, the Sanborn chart drive was engaged, and when the test surface reached a predetermined temperature, the test package was released. After the package impacted on the buffer, the chart drive was disengaged and the instrumentation recali-. brated. For the high-speed motion pictures of film boiling at (a/g) = 1 the flat walled glass tank (Fig. 10) was filled with water and the unsilvered glass dewar filled with liquid nitrogen. Illumination and camera focus were checked, and the thermocouple recorder was calibrated. The high-intensity lights were not turned on until the test object had been placed in the liquid nitrogen, to limit radiant heating. When the test surface temperature reached a predetermined level, the camera shutter was opened. The exposure time used provided 60 to 80 frames of film boiling. The remainder of the unexposed frames were used to photograph the non'boilsng state, immediately following the run, and served to indicate the precise

43 location of the heater surface, which was obscured while boiling was taking place.

CHAPTER V DATA REDUCTION The following sections describe the techniques used in obtaining from the raw data the numerical values of time, temperature, pressure, acceleration, -saturation temperature, heat flux, Nusselt number, and modified Rayleigh number. The procedure used in reducing the photographic results is described. Also included for each measured parameter is an estimate of the errors involved. A. TIME Time was obtained on a relative basis only and was used as a reference and correlating parameter. All data (except photographic) are referred to a zero reference time which was taken as occurring 3.8 seconds before test package impact when the data permitted. This allowed up to 2.4 seconds of (a/g) = 1 data to be reduced in addition to the free fall or fractional gravity data. The time indication was provided by timing marks on the Sanborn recorder (Figs. 11 and 12). The location of the timing mark on the strip chart could be read to within ~0.2 mm. At the normal chart speed of 100 mm/second, this corresponds to ~0.002 second. It was necessary to interpolate between the 1-second marks to obtain the times at which the temperatures were read. These intervals varied from 0.2 second in the film-boiling region to less than 0.05 second in the peak heat flux region. The intervals used were chosen so that

' I*,:, / ~ ".... [ i,. i',:::I....... i ~' ~~~ ~~~~1::::1 ~~~~~~~~~~~~li~(ri:':.........':......."ICE REFERENCE JUNCTION -' [...;' i * i....,,... "'.... ""iif~iti~cfT~~if.,'~................. -* -- ----- "SPHERE DIFFERENTIAL TEMP.-~~~r 1,ct:.*,o....., -'*""-~~........"'........f~i: i~itf~if.... ~ ~.....................,......'~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ ~ ~.!:**:-* -**.....i —T:!........... 0.1 Mv TCLSPHERE >Tsurf'ce i, t~-..... CALR,,ATION,*~...u.i I 4t:.:,.i::.'...... ":.....,._~~~i_ A - - - - - i-.l:: I UID NUCLOENATEP-._:..1.411.......... ~)~~. ~.i~~ ~ firliii {....:-.:...,....;...., ~, *,((~~,~I~~(;.,..,....:' I''' i: Ll':t::~;:::I::;; ~?,~ ~ I~r:.1 ~:::'~l[::'~,~'' ri1:: I ~ ~1....:' [............. — ~. ~r;, rr~, L ct*~ r~~~ ~~~~ ~~r, ~..-4m v SPHE RE TEMP.~~, ~~~~ ~. NITROGEN TM:. P ~~~~r~,r-r~ (~LI 1~ ~-t!~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ i-~~~~~~~~~~~~~~~~~~~~-................... -......~-.~:::.,::::-:_..i.:.: ". i:.._'~~'-~ "' t. "'iiiii*,,::...,.... ~,,,,..-..,.,., ~-:- 1 -..,......... ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~".:1::::':,!'::''-~" "' "" f:-t A"-..T..P:'"~~...~ ~,r...:':':!::.....ii,,i........;1"....'.':2 "7 C5 "3C,? eI- A f4r4owm,,.....~~~~~1,,..'.*,,..... | r'' Fig. 11.Tp lrc ot e u wtd t copper sphere with film boiling of liquid nitrogen. (a/g) = 1.

S~~~~~~~~ I I I I m[tw. 1. I!!l'.:jij 1 itttttttt(110ttttttt|,,: ~::t~,, ~i "tt.i S~: HER~ COPPERNT L EM t#|}tttflti itttt[8 it i o 3 1 t i f pi i: i~ 2 }I COPPER tCONSTANTAN m i {;,v~vU,t4,} Xt t 1 -''' T' NI I I ii ":' 1i' "+ iI 1 H 1 ~ *- t1 H-t ~i1'S 4 1 1 11! Oz ~f tf 1:13 1l 0 Tf T t ICE REFERENCE JUN CTO 1 N0~ ~~ ~ ~+ =t~T r. SPHERE DIFFERENTIAL T* ML -l HEi MP' |~mit+U+tjU~"' LL~tt.Ei:1i'+'-:i!lf *':Ji.ttl..lteli. l.,...,,. I!v L!~ _ Fl lEALI I I I-lii — ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~: W - ---:i,'' I'', I -fl MM $; t~? i,,;:1 SPHERE DIFRNILTEM P fffffffftLi ff~Jtttit ti~~~~' t~tr:' ~.... i*~~~~~~~* ~~~~~~~$( t _11'4.1~144 t 4 Fig.. I.. oCL > Tiurfaco d and trnstOnbi.I+ mvg t ci) ~r~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ 11 I I L1 ) ) L XX 14r: lit I HT, ii i~Hf tti r 11,, rtit i ii t: t f StS!S~ttt~.: ttti~tttt ~ St11 ih A +l I. ~!....:..:.I: J i.......... S H R E P:r:~~~~~~~~~~~~~-:~1 i 1+i I~ i i'd i!.. —--.S....-.-.. —.-. I.~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~...... i iiI t'I i I f i; I j;~~~!!i W~~ ~~......-!'...."!.....-!"!'!-.........,~~~~~~~~~c''.":........,~~~~~ I I I I I I II I I i f. -S~~~~~~tS~~~~~urn tfre e falitl w it nce te and tras itionf botiing. (a/g i ~: Opp 5.2 0 mv............. SECtr; 1 i-JI, O:: ~ i......:: - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - (* t~. f~i!~Stti:1: iFig. 12. Typica; l oscllorapicrecrd urng reefal wth uclat andtrasiton oilng.(a/);e 0

for each interval the value of ATsat (see Section V.F) was approximately constant, but with no interval longer than 0.2 second. These interval marks could be read to within +0.2 mm, or +0.002 second. The maximum error possible in time determination is +0.005 second, but probably will not exceed ~0.003 second. B. TEMPERATURE The output from the various thermocouples was recorded on Sanborn charts in the form of pen deflection vs. time (see Figs. 11 and 12). The recorder was calibrated for the millivolt range of interest both before and after the test run. These calibration marks are recorded as deflections which correspond to the various calibration voltages, and thus to the thermocouple temperatures which would produce those voltages. The deflections corresponding to the millivolt calibrations and data are measured and recorded as a function of time and converted to temperature values using the thermocouple calibration curve derived for the thermocouple wire which was used. One roll each of copper and constantan 30-gauge thermocouple wire had been obtained and calibrated with a nitrogen vapor pressure cryostat, at the C02, and mercury freezing points, and the steam point. The calibrationfor these particular wires, rather than the standard copper-constantan conversion tables, was used for all data reduction. All thermocouples were made from these two rolls of wire. Sanborn recorder pen deflections could be determined to within +0.2 mm, which corresponds to approximately +0.20F at liquid nitrogen temperatures

48 when the recorder is operating at maximum sensitivity. This is taken to be the error in relative temperature measurements. To determine the error in absolute temperature measurement, liquid nitrogen temperature measurements were made during every test series at one atmosphere, saturated conditions. The local pressure was obtained from a barometer, and the saturation temperature of the liquid nitrogen was determined from tables57 to the nearest 0. 1F. The measured value of the liquid nitrogen temperature did not deviate from the calculated temperature by more than ~0.5~F, including reading errors as discussed above. This value, ~0.50F, is taken to be the maximum error in absolute temperature determination. C. PRESSURE The pressure transducer was calibrated to within ~0.5 psi at 30 psig and 60 psig, which were the nominal values for the elevated pressure tests. The Sanborn recorder pen deflection was read to within ~+02 mm, which corresponds to ~0.2 psig at 30 psig, and ~0.4 psi at 60 psig. The pressure at which a run started was regulated manually to within ~1 psi of the nominal pressure, and an attempt was made to keep the pressure on the low side of this range at the start of the test. The duration of a test during fractional gravity conditions was so short (< 2 seconds) that regulation of pressure during this interval was not considered necessary, since the relatively large volume of the container served to minimize the potential pressure rise due to vapor generation~ Pressure increased'between the time that the relief valve was closed and the time that

49 the test package was dropped, and values of this increase were as much as 1 psi at 30 psig and 2 psi at 60 psig. Measured values of pressure therefore varied from 43.3 psia to 46.3 psia at a nominal 3 atmospheres (44.1 psia). The average value of the pressure measured during a run was used for calculations for that particular run. D. SATURATION TEMPERATURE The saturation temperature was determined as a function of the pressure at the time of measurement. When saturated liquid tests were being run it was possible to check the tabulated value for that pressure37 against the value indicated by the liquid thermocouples. These values were found to agree within the +~O.5F indicated above for thermocouple error in absolute temperature determination. For subcooled tests it was not possible to determine saturation temperature independently by the thermocouple measurements, so it was necessary to use the tabulated value corresponding to the measured. pressure in the test vessel. Based on the results obtained under saturated conditions, the determination of saturation temperature under subcooled conditions is estimated to have the same error, i.e., ~0.50F. The value of Ts-Tsat, or ATsat, is subject to ~0.5~F errors in the determination of both T s and Tsat, so that the maximum error in ATsat is +~1F. E. ACCELERATION The fixture used to calibrate the accelerometer measured the angle between the normal gravity vector and the sensitive axis of the accelerometer.

50 The angular position was known to within ~0.0005 radian (position locations were accurate to within +0.002 inch on the periphery of the calibration disk, which is 10 inches in diameter) and the direction of the normal gravity vector was determined to within ~0.0005 radian (checked against spirit levels and the accelerometer itself, which has maximum positive voltage output at (a/g) = +1 and maximum negative voltage output at (a/g) = -1). The acceleration measured by the accelerometer is equal to the product of the normal acceleration and the cosine of the angle between the normal acceleration vector and the sensitive axis of the accelerometer. The maximum error in the accelerometer measurement thus corresponds to a maximum error in (a/g) of +0.001. Two values of (a/g) were of primary interest: those corresponding to free-fall and to counterweighted drop utilizing the empty counterweight. The test package was prepared exactly as it would be for a normal data-taking run except that none of the pressure and temperature instrumentation was used. The accelerometer was installed and calibrated for the region of interest, with the sensitivity setting on the Sanborn recorder being determined by the region being investigated (higher sensitivity was required for free-fall tests). Operation under free-fall tests revealed a noise level for the accelerometer-recorder system which corresponded to a level of (a/g) of 0.001, owing primarily to AC pickup. Reading errors in this range corresponded to a variation in (a.g) of +0.0002. The value of (a/g) measured during free fall was less than the AC pickup, so it was read as 0.001~0.001, i.e., less than 0.002.

51 No AC pickup problem existed with the fractional gravity tests, and the error corresponded to a variation in (a/g) of +0.001. The actual fractional gravity tests revealed periodic fluctuations about an average value of (a/g). These were attributed to a spring-mass type coupling of the counterweight and the test package with the steel cable acting as a spring. This problem is discussed in more detail in Appendix E. Reading and calibration errors were negligible compared with these oscillations, which limited the accuracy of the determination of (a/g) to approximately ~0.01 in the range of (a/g) of 0.17. F. HEAT FLUX Heat flux, or (q/A), was determined from a combination of the properties of the test object and the quantities measured during the tests. A first law analysis assuming a lumped system shows that the heat flux may be expressed as the time rate of enthalpy change of the test object_ or q = m dh V Cp (T) dT A A dt A P dt The heat flux can'be calculated from the slope of the cooling data (temperature vs. time) and the known'body properties. To determine the value of Cp(T) the experimental data for pure copper were plotted as Cp vs. T. A curve was fitted to these data (Fig. 13) and Cp was read directly as a function of T. The maximum deviation'between the two sets of experimental data is estimated to be less than 5% below 2000R. and less than 2% above 2000R.

o09.08.07.06 — /J~ O~ Ref. 38 Ref. 39.05.04.03 Fig. 13. Speciftic heat of copper. Tempratren + R

53 A system usually may be treated as a lumped system when the Biot Number is very small (see Appendix D). In the film-boiling region, the Biot Number corresponding to the test objects used here has an order of magnitude of 0.005, so that the assumption of a lumped system in this region is reasonable. In the region near peak heat flux the value of the Biot Number approaches 0.5 and the system may no longer be treated as lumped. For this case it is necessary to use the form of Eq. (5) where (q/A) is expressed in terms of dh/dt, the rate of change of total enthalpy of the test object, since both T and Cp(T) vary over the volume of the test object. In the film boiling region the value of dT/dt ranges from 1 to 200F per second, depending on the test surface geometry, size, and temperature. Only a small temperature change is covered in a single test with fractional gravity. The value of d2T/dt2 is very small in the film-boiling region in this short time interval, so that the value of dT/dt is considered constant for a particular value of (a/g). In the transition and nucleate boiling region, the value of dT/dt was normally in the 10 to 50~F per second range (to 2000F per second for the 1/4-inch diameter sphere) and d2T/dt2 was also large. A much higher data sampling frequency was utilized in reducing these data, and the reduced data were punched into IBM cards. A computer program was written for the IBM 7090 to calculate the values of (q/A) as a function of ATsat. The program treats the sphere as 10 concentric spherical segments and utilizes a finite difference technique to evaluate the rate of total enthalpy change of the entire system, using the measurements as input at the outer shell.

54 The calculated difference in the temperature of the sphere at the center and at the surface was found to be in good agreement with experimentally measured values in the peak heat flux region (typically of the order of 2 or 3~F). The program included as output a plot of input time vs. temperature data, a logarithmic plot of (q/A) vs. ATsat (including a typical plot for the 1-inch diameter sphere at (a/g) = 1 for comparison purposes), and a plot of (q/A) vs. time. Samples of the input to the computer are shown in Fig. 14, and samples of the output from the computer are shown in Fig. 15. TOS-8 is the identification for the 1-inch diameter sphere. "R" indicates when the package was released. A flow diagram and listing of the program are included in Appendix D. The error in the determination of (q/A) may be approximated by the errors in determining dT/dt. The value dT/dt is obtained by measuring the slope of the curve drawn through the time-temperature data points. In the film-boiling region, the dT/dt for the 1-inch diameter sphere and the disk were approximately equal, while the dT/dt for the 1/4-inch diameter sphere under the same conditions was approximately six times higher than it was for the 1-inch diameter sphere. The temperature could be read to ~0.2~F (see Section V.B), and the time could be read to +0.003 second (see Section V.A). The typical increments of temperature and time, regardless of test object or boiling region, produced a maximum error due to reading inaccuracies of +20%o The (q/A) vs. ATsat data were repeated within this range for most of the tests. Repeatability varied with the test object and boiling region.

RUN NO. 60G, 1/10/64, TOS-8, 0 G, HE PR. 45 PSIA, SUBCOOLING=17F CALCULATION 94 = 45, N = 5, RO = 558.000000, VOA =.013889 PARAMETERS DR = 4.1670006-03, TC = 290.000000, DS = 10.0OOOOO0-04, SM = 11 RZ =.041670, TSAT = -301.000000 TIME,SEC TIM( 1)...TIM(45) RELEASE AT 0.51 SEC.000000E+ 5.000000-)t02 i. 00(!00E-01 1.500000E-01 2.000000E-01 2. 500000E-01 3. 000000E-01 3.250000E-01 3.500000F-01 3. 753000E-01 4.0 0000tE-01 4.250000E-01 4.500000E-01 4.750000E-01 5.000000F-(1 5.250)000E-01 5.50000(,E-01 5.750000E-01 6.0()0000E-01 6.250000E-01 6.500000E-01 7. 500000E-01 8.(0000000F-01 8. 500000E-01 9. 0000OE-01 9.500000E-Ol 1.00 O00E+00 1.050000E+00 1.100300E+00 1.150000E+00 1.200000E+00 1.250000E+00 1.3000002C+00 1. 350000E+00 1.400000E+00 1.450000E+00 1.500OO3)E+00 1. 550000E+00 1.60000EC+00 1.650000E+00 1.700000)E+00 1.750000E+00 1.800000E+00 1.650000E+00 1.900000F+00 TEMPERATURE, ~F TE' (1)... TEM( 45) -2. 584400E+02 -2. 52500E+02 -2.602000E+02 -2.611800E+02 -2.623300E+02 -2.63480JE+02 -2.649000E+02 -2.657600E+02 -2.666000E+02 -2.746500E+02 -2.68400:)E+02 -2.694000E+02 -2.7U04300t+02 -2. 714000(+02 -2. 74h00+02 -2.735500E+02 -2. 746500 SE+02 -2. 75 i00+02 -2. 77 E+02 -2.777006E+02 -2.776600+02 -. 780800)E+02 -2. 79500E+02 -2.6'1l0L+02 -2.806500E+02 -2.310800E+02 -2.614800E+02 -2. F1600E+02 -2.d24000E+02 -2. 829400 +02 -2. 635o0 +02 -2. 842200E+02 -2. 849800E+02 -2. 356500E+02 -2. c86 3000E+ 02 -2.8 94 00E+02 -2.875600E+02 -2.880500E+02 -2.886000U +02 -2. b920OCE+02 -2.694200E+02 -2. 89780()E+02 -2. 900800E + 02 -2. 904000E+02 -2.906200E+02 -2. 908800E+02 (a) Tabular input. l —------------------------------------ I I I I I I I I I T I I I I I I I I I I UJ P I I I I E I I I I R I I II I A I I I I I T I I I I I U I I I I I R I I II E: I I I I I + 1 I I -250. 000 +-* —*-* + —-+~+++ D I * * IR I I I E I *** I I G I ** I I tc aI* I I I F I 3** I I I I I +: 1 I I I I * * I I I I I * * * # * I I I I ** * * I I I I I * * * * I I I I I * * * * * -* I I I I I * I I I I I I I I I I I -300.000 + -- - + —-----------------------— +-+~+ 0. 000 0. 500 1.000 1.500 2.000 RELATIVE TIME, SECONDS RUN NO. 60G, 1/10/64, ICS-8, O G, HE PR. 45 PSIA/, SUJBCOOLING=17F (b) Computer plot of input. Fig. 14. Typical input to computer.

RUN NO. 60G, 1/10/64, TOS-8, 0 G, HE PR. 45 PSIA, SUBCOOLING=17F ATSAT,~F DTT (1)... DTT(39) 3.980273E+01 3.870377E+01 3.748254E+01 3.606267E+01 3.526641E+01 3.443182E+01 3.352295E+01 3.260134E+01 3.161106E+01 3.060602E+01 2.957911E+01 2.853042E+01 2.744999E+01 2.630710E+01 2.515055E+01 2.377785E+01 2. 320514E+01 2.275236E+01 2.150197E+0,1 2.080997E+01 2.031088E+01 1.992554E+01 1.952208E+01 1.909059E+0 1 1. 860385E+01 1. 804663E+01 1.742474E+01 1. 674701E+01 1.604855E+Oi 1.535707E+01 1.468774E+01 1.406399E+01 1.348287E+01 1.290273E+0-1 1.237276E+01 1.192025E+01 1.152394E+01 1.121276E+01 1.091942E+01 (q/A),BTU/HR-FT2 QAB(1)... AB(,39) 2.545516E+04 2.792063E+04 3.128989E+04 3.703239E+04 3.714034E+04 3.876963E+04 4.088780E+04 4,278188E+04 4.514705E+04 4.588960E+04 4.698259E+04 4.803795E+04 4.904361E+04 5.183785E+04 5.246566E+04 5.095114E+04 3. 387158E+04 2.446783E+04 1.723067E+04 1.521606E+04 1. 208865E+04 1.005197E+04 9.852527E+03 1.058652E+04 1.201851E+04 1.350115E+04 1.495908E+04 1.625311E+04 1.653247E+04 1.607383E+04 1.561982E+04 1.476045E+04 1. 350948E+04 1.329963E+04 1.252756E+04 1.046292E+04 8.420788E+03 7.528122E+03 7.201100E+03 ATSAT'F DATAX ( 1)...DATAX(3 9) 3.980273E+01 3.870377E+01 3.748254E+01 3.606267E+01 3.526641E+01 3.443182E+O01 3.352295E+01 3.260134E+01 3.161106E+01 3. 060602E+ 01 2.957911E+01 2.853042E+01 2.744999E+01 2.630710E+01 2.515055E+01 2.377785E+O1 2. 320514E+01 2.275236E+01 2.150197E+01 2.080997E+01 2.031088E+01 1.992554E+01 1.952208E+01 1.909059E+O1 1. 860385E+01 1.804663E+01 1. 742474E+01 1.674701E+01 1.604855E+01 1.535707E+01 1.468774E+01 1.406399E+01 1.348287E+01 1.290273E+01 1.237276E+01 1.192025E+01 1.152394E+01 1.121276E+01 1.091942E+01 TIME, SEC TIM(1... TIM(45).000000E+00 5.OOOOOO000000E-02 1.OOOOOOE-01 1.500000E-01 2.000000E-01 2.500000E-01 3.000000E-01 3.250000E-01 3.500000E-01 3.750000E-01 4.OOOOOOE-01 4.250000E-01 4.500000E-01 4.750000E-01 5.000000E-01 5.250000E-01 5.500000E-01 5.750000E-01 6. OOOOOOE-01 6.250000E-01 6.500000E-01 7.500000E-01 8.OOOOOOE-01 8.500000E-01 9.OOOOOOE-01 9.500000E-01 1.00OOOOE+00 1.050000E+00 1.100000E+00 1.150000E+00 1.200000E+00 i 1.250000E+00 1. 300000E+00 1. 350000E+00 1.400000E+00 1.450000E+00. 500000E+00 1. 550000E+00 1.600000E+00 1.650000E+00 1.700000E+00 1.750000E+00 1.800000E+00 1.850000E+00 1.900000E+00 (a) Tabular output. Fig. 15. Typical output from computer.

5.000 + +..... +-...+ —-— + —+ —+ —++-+ + —---— ++ +-_.-.-. —.-.+ - +-++-++' ~~+ + +...... + + + + I I I I + + + + L I R I I 0 + + + + G II **, I I + ee + + Q 1I... ** I I / + +.. + + A I * I I I I. * ~ I I + +. * + + B I.. * I I T I I *. * I I U I I I I / 4 +.. +4 H I I I R I I * I I -I I *4 * I I F * I I T I I * * I I 2 I I.* *. I I I I * I I 4. 000 +.. +- + — + —- +- + +- +* —..*.+ —. + — +- -+-+-_+ +-+__ __+_._..+___+__ +__+_ +_++_+ + + + + +.4. + + II * ~ I I +.+* +.+ ~~~~~I ~I I.. I U 4+.+ * + *- +4. I I I.. I +. + +... + I I ~ I.. I +. + + ~ + I I I.. I I. I I.. I 4+ 4+ + + I. I... I I. I..I I I. I.. I I +. +.. + + I *. I... I I. I.... I I I I I i I. I I I I. I I I I I I I I I I I 3.0 0 ~+ +..+- -- + ++++ — + —-—.+ — + —+ —+-+-+ +_4+-+-..__+___+ ___+__ +__+,. +_++_ 0. 000 1.000 2.000 3.000 LOG (TS-TSAT), DfEGREES F RUN NO. 60G, 1/10/64, TOS-8, 0 G, HE PR. 45 PSIA, SU8COOLING=17F (b) Heat flux vs. aTsat. Fig. 15 (Continued)

80000.000 +- - +- - ------— _ _ -______+ I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I IR I I I Q I I I I / I Ii * I I I A I * * I I I I *** I I I I ** I I I B I * I I I I T40000.000 +~~ - ~ ~~ ~~~~ —+ —---------- U I ** I I I I / I I * I I I H I * I I I I R I I I I I - I * * I I I I F I I * I I I T I I I I I 2 I I I I I I I * * I * * * ** * I I I I I * * * ** I,l I I ** * I * I cD I I I I * * * I I I I 1 I I I I I I 0. 000 + + + —-~ ~ ~_ _ _ ~ ~ ~~+~+ 0.000 0.500 1.000 1.500 2.000 RELATIVE TIME, SECONDS RUN NO. 60G, 1/10/64, TOS-8, O G, HE PR. 45 PSIA, SUBCOOLING=17F (c) Heat flux vs. time. Fig. 15 (Concluded)

59 All 1-inch diameter sphere data and the 1/4-inch diameter sphere data with film boiling repeated within a few percent; the disk data seldom repeated to better than ~10%, and the nucleate boiling data with the 1/4-inch sphere varied by +20% or more, due primarily to the very large rate of change of temperature. G. NUSSELT NUMBER, Nu The Nusselt Number, (hD/k), may be expressed in terms of the heat flux and ATsat as follows: Nu = hD D/A D q D6) kvf ATsat kvf A kvfATsat The value of (q/A) was determined as indicated in Section V.F, D is a constant for each test object and kvf and ATsat are functions only of the temperature of the test surface at the point where the heat flux was evaluated. The term l/kvfATsat was plotted as a function of ATsat. For a given ATsat.and (q/A), the Nusselt Number was calculated using the appropriate value of the body parameter D. H. MODIFIED RAYLEIGH NUMBER, Ra' Natural convection heat transfer data may be correlatedl by an equation of the form Nu = C[Gr Pr]n (7) = C [D3p(Ts-T)a C (8) w t2 where the product Gr.Pr is known as the Rayleigh Number, Ra, and ~ is the

60 coefficient of volumetric expansion. Frederking40 has expressed the single phase Rayleigh Number as D3p(p,-p)Cpa Ra = ok Bromley27 correlated film boiling heat transfer data with an equation of the form n h = C |hfgk's vfpvf(p-pvf" (10) L D4vfATsat which can also be written as u = Pvf(P-pvf)a hfg (11) Lvf \~k/vf CpATsat or Nu = C Ra CATsat (12) The term in square brackets in Eq. (11) serves the same function in correlating film boiling heat transfer data that the Rayleigh Number serves in correlating natural convection heat transfer data, and therefore is referred to as a modified Rayleigh Number, Ral. The term hfg takes into account a portion of the superheat in the vapor film as well as the heat required to vaporize the liquid, and is expressed as fg = hfg + CCpATsat (1 where C1 was given as 0.4by Bromley but is now generally taken to be 0.5 (e.g., Refs. 19, 51). Frederking40 has observed that when the superheat

CpATsat >> hfg, the term h + constant as fg + O, and the product CpATsat CpATsat h Ra hfg reduces to the ordinary single phase Rayleigh Number. This in CpATsat turn becomes the product of Gr and Pr when, for small ATsat, the density difference is expressed in terms of ATsat by means of the isobaric coefficient of thermal expansion. The modified Rayleigh Number may be written as, Ra' D3p(p-p)g (p C+ 0.5) () (14) -)2 \k kf CpATsat If it is written as the product of three terms, ~RaT = { tf f(Pefg (C I) hf + 0.5 t r)t ki korf ec CpATsat the first term is a constant for each test object, while the second term is a function of ATsat and pressure. A plot of the value of the second term vs. ATsat was made for pressures of 1, 3, 5 atmospheres, using properties as given in Ref. 37 and 41. I. PHOTOGRAPHS The high-speed photographs provided a means of obtaining the vapor film shape and thickness for the various geometries investigated. This permitted comparisons to be made of the effects of changing disk orientation, geometry and ATsat on the vapor film shape and thickness. The test procedure limited coverage to P = 1 atmosphere, saturated liquid conditions. The photographic data were obtained as seqpences of negative frames on a 16 mm format. A wire framework was placed near each test surface to pro

62 vide a measurement reference. The dimensions of these frameworks, which appeared on all photographs, were measured to +0.0005 inch. The negatives were back projected onto a ground glass screen with a magnification of approximately 50:1. A tracing was made of the test surface for each combination of test surface and ATsat. A sequence of approximately five frames was chosen for each combination of geometry, orientation, and ATsat, and the film outlines were superimposed on the test surface tracing. For the sphere, the complete film surface was included; for the disk, approximately five representative points along the surface were included. The film thicknesses were measured on the tracings and, using the measured reference wire framework, corrected to absolute physical dimensions. The reading error in these measurements corresponds to ~0.010 inch. Another source of uncertainty exists in the assumption that the measured film thickness is representative of film thickness at all points on the test surface. Although short-lived protuberances were deliberately avoided in selecting representative points at which to make the measurements, those made on the disk give the maximum film thickness along a chord. Measurements taken on the sphere probably indicate the local film thickness.

CHAPTER VI RESULTS A. GENERAL The experimental results are presented under three major headings: Film Boiling, Other Boiling Regimes, and Photographic Results for Film Boiling. The results included under the first two headings are presented on graphs showing the relationship between heat flux, (q/A), and the difference between the test object temperature and the saturated liquid temperature, ATsat, for the other variables considered. The photographic results of film boiling are presented as composite drawings of vapor film thickness for a sequence of frames. All results were obtained using liquid nitrogen as the test fluid, "Saturated boiling" is used to indicate boiling with a liquid under saturated conditions; "subcooled boiling" indicates boiling with a liquid which has a bulk temperature lower than the saturation temperature. Comparison of heat fluxes for the different variables is made by plotting them against ATsat. The use of log-log coordinates permits the data to be presented conveniently over the approximately two orders of magnitude variation which was obtained for both (q/A) and ATsat. A standard (q/A) vs. ATsat curve was developed based on the data obtained by Merte, et al,,19 with the 1-inch diameter sphere in boiling saturated liquid nitrogen at one atmosphere pressure and (a/g) = 1. This curve, or a portion of it, is included on most of the figures for reference purposes. 63

64 Various test surface geometries and orientations were used, and the effects of these variations are shown in terms of (q/A) vs. ATsat for the film boiling-regime. The pressure and the liquid subcooling were varied, and the effects of these on boiling are shown. The effects of changing (a/g) in addition to the above variables are shown. Only spherical test surfaces were used for tests in boiling regimes other than the film-boiling regime. The temperature behavior of a test surface at (a/g) = 1 is characterized by a "quasi-steady" change of temperature with time, i.e., there are no discontinuous changes in the slope of the time-temperature curve. When the test package is dropped, a discontinuity in the time-temperature curve is observed, followed by the establishment of a new quasi-steady condition with a different slope of the time-temperature curve. The period of time'between the discontinuity and the new quasi-steady condition represents a transitory period between two levels of (a/g), and is shown in the figures by a dotted line connecting two data points. B, EXPERIMENTAL RESULTS 1. Film Boiling Film boiling data were obtained for all geometries, orientations, subcoolings, pressures, and accelerations which were investigated. The effects of each variable except acceleration on (q/A) vs. ATsat are presented individually, and then the effects of acceleration on each of the other vari'ables are presented.

65 a. The Effects of Geometry and Orientation The (q/A) vs. ATsat data at (a/g) = 1 for saturated film boiling at P = 1 atmosphere are shown in Fig. 16 for the 1-inch and 1/4-inch diameter spheres and for the disk in the orientations designated as vertical (V), horizontal heating up (HU), and horizontal heating down (HD)o The points shown for the 1/4-inch diameter sphere and the disk include all data obtained under these conditions. For a given ATsat, the value of (q/A) for the 1/4-inch diameter sphere is approximately 20% higher than the corresponding value of (q/A) for the 1inch diameter sphere. The heat flux for the disk in all three orientations is approximately 100% higher than the heat flux for the 1-inch diameter sphere at the same ATsat. A larger range in variation of (q/A) at a given ATsat was generally observed for the disk than for the spheres. Some of the 1/4-inch diameter sphere data points obtained at ATsat less than 800F may indicate the beginning of the transition'boiling region. b. The Effects of Pressure The (q/A) vs. ATsat data for saturated film boiling at (a/g) = 1 are shown in Fig. 17 for the 1-inch diameter sphere at 1, 3, and 5 atmospheres. For a given ATsat, the heat flux is more than 40% higher at 3 atmospheres, and more than 60% higher at 5 atmospheres, than at 1 atmosphere. Results obtained using the 1/4-inch diameter sphere and the disk in all three orientations also exhibited a similar increase in heat flux with increasing pressure for a given ATsat in saturated film boiling.

10 Test Surface Run Numbers 0 1" Dia. Sphere Ref. 19 1/4" Dia. Sphere 63 A,B,J,K,N, 72 A,B,C,I,J,K,L,M,T O Disk - Vertical 65 A, 66 A,B,C, 67 A,B,C V Disk - Heating Upward 69 A, G,H,:, 71 D,E,F A Disk - Heating Downward 70 A,G,H,IT 71 A, C P 1 atm (a/g) =1 Disk - All Orientations 41 _P IU /4 Dia. Sphere CH'4 110 -PA Pq 0, 0I~~~~~~~~~~~0 Reference Curve 0 0 1? Dia. Sphere 0 0 103 1 10 100 1000 AT,0F sat'O Fig. I6. Effects of geometry and orientation on saturated film boiling.

105 P, atm Run Numbers _ 1 Ref. 19 o 3 57 M,N, 64 M,O, 77 F,I L^ 5 57 K,L, 64 L,N, 73 D, 77 A,B,C,D,E,H 1-inch Diameter Sphere P = 5 atm P 3 atm F, 1o p Reference Curve P = 1 atm 103 ~~~~~~~1 ~10 100 100 AT OF Fig. 17. Effect of pressure on saturated film boiling.

68 c. The Effects of Subcooling The (q/A) vs. ATsat data at (a/g) = 1 film boiling conditions with 5 atmospheres pressure are shown in Fig. 18 for the 1-inch diameter sphere at both saturated and subcooled conditions. For these test conditions the use of subcooled liquid increased the heat flux from the test surface approximately 50% over that obtained using saturated liquid at a given ATsat Results obtained at 3 atmospheres pressure with the 1-inch diameter sphere and at both 3 and 5 atmospheres for the other test surfaces were similar. For a given ATsat, the heat flux ranged from 10% to 60% higher with subcooled liquid than with saturated liquid. d. The Effects of (a/g) The (q/A) vs. ATsat data at 1 atmosphere film boiling conditions are shown in Fig. 19a for the 1-inch diameter sphere with (a/g) = 1, (a/g) = 0.17, and (a/g) - 0 (free fall). Two different free-fall conditions are shown. A value of (a/g) in the range of 0.01 to 0.03 was measured using the first test package in free fall, and was due primarly to air drag. A value of (a/g) of 0.001~0.001 was measured using the second test package in free fall, the decrease being due to use of the inner free vessel concept. A continuously decreasing heat flux was measured during free fall with the second package, The heat fluxes obtained after the transitory periods associated with the change from (a/g) = 1 to free fall are shown as two data points connected by a solid line. The point labeled "E" indicates the earliest heat flux data after the transitory period, and the point labeled "L" indicates the last heat flux data obtained prior to impact of

10 Run Numbers o Saturated 57 K,L, 64 L,N, 73 D, 77 A,B,C,D,E,H o Subcooled 56 I, 57 F,G,H, 61 A,B,C,D,E, 64 A,C,F,H (Range 220-330; Average 260) 1-inch Diameter Sphere P = 5 atm (a/g) =1 Subcooled Saturated ~ 4 10 00~~~~~~~~~~~~~~\ Reference Curve 0 P=l atm 103 L II II lI I1 I 1I 1 10 100 1000 AT 0F sat' Fig. 18. Effect of subcooling on film boiling.

104 rI- l-inch Diameter SphereI a/u1 —nch Diameter Sphere a. 1-inch Diameter Sphere b 1/h-inch Diameter Sp a/g Run Numbers atm 0 <0.002 52 E,F,G,H,I,J,M,N i I 1/4-inch Diameter Sphere 1.0 72 A,B,C,K,L,M,T \ (a/) = 0.20 1 0.002 72 I,J I 1 I:1' 1 L Il 0.01<(a/g)<0.03 3-3 % I I E Reference Curve ~~10~~~a = I E ~~~~~~~1~(a/g)4<0.002 1-inch Diameter Spher? l ( a/g L E L 10! IL 50 100 400oo 60 100 400 AT OF sat' Fig. 19. Effect of (a/g) on saturated film boiling on spheres.

71 the test package on the buffer. The solid line represents intermediate values. The heat fluxes measured at (a/g) = 0.17 are approximately 60% of those obtained at (a/g) = 1 for a given ATsat. The heat fluxes at (a/g) = 0.01 to 0.03 are approximately 35% of those at (a/g) = 1 for a given ATsat. The heat fluxes at (a/g) < 0.002 show a large amount of variation, ranging from 40% to less than 10% of the heat flux at (a/g) = 1 for the points labeled "E," and a similar variation for the points labeled "L." Film boiling data were obtained with the 1-inch diameter sphere at 3 and 5 atmospheres pressure at (a/g) = 0.17 for both saturated and subcooled liquid. Data were also taken for the subcooled case at elevated pressures and with free fall, but not for saturated liquid at higher pressures. The results obtained with subcooling were similar to those shown in Fig. 19a, i.e., for a given ATsat, a decrease in (a/g) was accompanied by a decrease in heat flux. The extremely low values of heat flux associated with freefall conditions at 1 atmosphere pressure (Fig. 19a) were not observed with the higher pressure tests with subcooled liquid, the average value of heat flux at a given ATsat decreasing to approximately 25% of the heat flux at (a/g) = 1, for the 1-inch diameter sphere. The (q/A) vs. ATsat data for the 1/4-inch diameter sphere are shown in Fig. 19b. The conditions were the same as for the 1-inch diameter sphere, i.e., film boiling at P = 1 atmosphere with (a/g) = 1, 0.17, and free fall. The effects of varying (a/g) are not as pronounced with the 1/4-inch diameter sphere as with the 1-inch diameter sphere. At (a/g) = 0.17 the heat flux

72 is approximately 70% (vs. 60% with the 1-inch diameter sphere) of the heat flux measured at (a/g) = 1 and the same ATsat. In free fall, the heat flux is approximately 50% (vs. 35% or less with the 1-inch diameter sphere) of the heat flux measured at (a/g) = 1 and the same ATsat. Single (q/A) vs. ATsat data points were obtained with the 1/4-inch diameter sphere at (a/g) = 0.17 at 3 and 5 atmospheres with saturated liquid. Results were obtained with subcooled liquid at 3 and 5 atmospheres at (a/g) = 0.17 and free fall. All of these results showed decreases in heat flux with decreasing (a/g) at a given ATsat similar to those shown for 1 atmosphere saturated film boiling. The (q/A) vs. ATsat data obtained with the disk in all three orientations at 1 atmosphere film boiling conditions with (a/g) = 1, 0.16, and free fall are shown in Fig. 20. The variation of heat flux at a given ATsat observed at (a/g) = 1 (quite large when compared with the variation of heat flux obtained using the 1-inch diameter sphere) may'be indicative of the variation of heat flux to be anticipated at (a/g) = 0.16 and free fall. One point was obtained for each orientation and ATsat at (a/g) = 0.16 and free fall, so no variations could be observed. The heat fluxes measured at (a/g) = 0.16 and free fall were always less than those at (a/g) = 1. This was also observed at pressures of 3 and 5 atmospheres using both saturated and subcooled liquid. However, no consistent orientation dependence is observed at any particular value of (a/g), as was noted also at (a/g) = 1 (Fig. 16) (e.g., although the heat flux from the vertical disk at a given ATsat in free fall was lower than that from the

73 Disk Orientation Run Numbers V HU HD V HU HD 1.00 |I A & 65 A 69 A 70 A o.16 O V A 66 A,B,C, 69 G,H,I 70 G,H,I <0.002 O 7 A 67 A,B,C 71 D,E,F 71 A,B,C, Disk P= 1 atm CMj -- _4 4 510 Reference Curve 1-inch Diameter Sphere 1o031 I I,I I I...... I, I I I I a I 50 100 4oo AT OF sat' Fig. 20. Effect of (a/g) on saturated film boiling on disks.

74 disk heating up or heating down at 1 atmosphere saturated conditions, this was not true at 5 atmospheres saturated conditions). 2. Other Boiling Regimes Time-temperature data were also obtained in the minimum heat flux, transition, peak heat flux, and nucleate boiling and free convection regimes using the spherical test surfaces. All 1/2-inch diameter sphere data were reported by Merte, et al.19 The 1/4-inch diameter sphere data in the peak heat flux and nucleate boiling regimes are subject to large errors owing to the very rapid temperature transient associated with the small heat capacity. The variations in the computed heat flux associated with these errors obscure the effects of the test variables. The experimental data for the 1/2inch and 1/4-inch diameter spheres are included in Appendix A. The heat flux-ATsat data obtained with the 1-inch diameter sphere, which are presented in this section, do not represent coverage of the variables investigated as completely as was the case in the film-boiling region. Emphasis is placed on presenting the effects of (a/g), subcooling, and pressure on boiling on the 1-inch diameter sphere in the various regimes. a. Minimum Heat Flux Boiling All of the (q/A) vs. ATsat data points obtained with the 1-inch diameter sphere which appeared to have the characteristics of the minimum heat flux ((q/A)min) are presented in Fig. 21a for saturated boiling at pressures of 1, 3, and 5 atmospheres. A (q/A)min point was obtained when a change in ATsat to either a larger or a smaller value was accompanied by an increase

102 - P, atm Run Numbers a. Effect of Pressure b. Effect of Subcooling 0- 1 Saturated Ref. 19 -03 Saturated 73C, 77F,I P=5atm 1-inch Diameter Sphere 1-inch Diameter Sphere (a/g) = 1 (a/g) = 1 -- A5 Saturated 73B, 77A,B,C,D,E,H P=3atm 4 Saturated P=5atm - &*5 Subcooled 61D,E,H, 64H (Range 23~-- 330; Average P=latm 290) CM F, 10 P=5atm Sat P=3atm P=latm Reference Curve Reference Curve/ P-latm P=latm Saturated 103 10 20 100 30 100 AT OF sat' Fig. 21. Effects of pressure and subcooling on (qJA)min and transition boiling.

76 in (q/A). Each point in Fig. 21a represents the (q/A)min from an individual test run. An increase in (q/A)min with increasing pressure may be seen in Fig. 21a. The value of ATsat at which (q/A)min occurs, (ATsat)min, does not appear to vary with changes in pressure. The effect of subcooling on (q/A)min is shown in Fig. 21b for 5 atmospheres. The influence of subcooling at 3 atmospheres pressure is similar. The (c/A)min with subcooling is between 50% and 100% higher than the (q/A)min with saturation. Subcooling does not appear to affect (ATsat)min. There is no apparent effect of the level of subcooling in the range of subcooling covered here. Merte and Clark,19 using a 1-inch diameter sphere, obtained (q/A) vs. ATsat data in the minimum heat flux region for 0 <(a/g)< 1. No specific effort was made to obtain data in this region at elevated pressures in the course of the present work, but a limited amount of data were obtained. Results obtained with the 1-inch diameter sphere near the minimum heat flux point are shown in Fig. 22 and indicate that (q/A)min is less than 2000 Btu/ft2-hr for (a/g) = 0.17 and saturated conditions at 3 and 5 atmospheres, less than 4000 Btu/ft2-hr for (a/g) = 0.17 and subcooled conditions at 3 and 5 atmospheres, and less than 2000 Btu/ft2-hr for free-fall and subcooled conditions at 3 and 5 atmospheres. No saturated boiling data were obtained at free fall at 3 and 5 atmospheres. The data of Merte and Clark19 at 1 atmosphere are also indicated on Fig. 22. b. Transition Boiling Typical (q/A) vs. ATsat data at (a/g) = 1 are presented in Fig. 21a

77 Liquid P,atm (a/g) Conditions Run No. * 3 0.17 Saturated 64 0 A 5 0.17 Saturated 64 N * 3 0.17 Subcooled 120F 64 E _ $ 5 0.17 Subcooled 230F 64 H O 3 <0.002 Subcooled 150F 59 D O 5 <0.002 Subcooled 290F 61 C 1-inch Diameter Sphere 10 CM Reference Curve Saturated Liquid P = 1 atm (a/g) =1 Ref. 19 (a/g)=l1 I (a/g) =0.2 a 0 O.O1<(a/g)0.i03 I 10 3 30 100 ATta ~F satt f Fig. 22. Effect of (a/g) on (q/A)min

78 for the transition boiling regime with the 1-inch diameter sphere and saturated conditions at pressures of 1, 3, and 5 atmospheres. Although the minimum and maximum heat flux increase with pressure the effect of pressure in the transition region appears minimal, if any. Data obtained in this region with subcooled liquids also appears to be indistinguishable from that for a saturated liquid. A limited amount of transition boiling data at (a/g) = 0.17 and free fall was obtained. These data are shown in Figs. 23, 24, and 25. When the test plackage was released at a value of ATsat larger than that at which peak heat flux occurred, a decrease in (q/A) to some minimum value was normally observed. This was followed by an increase in (q/A) which was assumed to be transition boiling. If the test package was released after peak heat flux had occurred, there were no indications of transition boiling (e.g., Fig. 23a). When the test package was released at a ATsat slightly higher than that at which peak heat flux occurs, any transition boiling which occurred at (a/g) < 1 also occurred during the transitory period (see Section VI.A) represented by the dotted lines in the figures (e.g., Fig. 24c). A few of the (a/g) = 1 data points are shown for each test run in Figs. 23, 24, and 25. The last data point obtained at (a/g) = 1 prior to the release of the test package is designated on the figures'by an "R." Figures 23, 24, and 25 do not show any consistent trends in transition boiling with changes in pressure, subcooling, or (a/g). Transition boiling (defined here as any boiling where a decrease in ATsat is accompanied by an increase in (q/A))is observed over a large range of ATsat between (ATsat)min

1-inch Diamter Sphere1-inch Diameter Sphere 1-inch Diameter Sphere P -i atm P = 1 atmP= at Saturated Liquid Saturated Liquid Saturated Liquid (a/g) (a/g) (a/g) 4 0 1. 0 1. 0 1. 5x10 0 0.01< a/g)<0.03 (Ref. 19) 0 0.20 (Ref. 19) 0 0.33 (Ref. 19) R R~~~~~~ ft R~~~R 6 ~~~~~~~~~~~~~~~RB CJ 4 ~210 Reference Curve (a/g) =1Reference Curve Reference Curve (a/g)=1 (a/g)=1 a. 0.01<(a,/g)<0.03 b. (a./g)= 0.20 C. (a/g)= 0.33 10 50 10 50 10 50 ATsat'O Fig. 23. Effect of (a/g) on transition boiling at one atmosphere..

10 - linch Diameter Sphere P = 3 atm Saturated Liquid \ (a/g) Run Nos. = — 1 o <01.002 77 F,G 4-d) 10 50 1 -inch Diameter Sphere R 1-inch Diameter Sphere R P = 3 atm P1 IY \ P I' 3 atm Subcooled Liquid Subcooled Liquid (140F - 170F) (120F-150F) (a/g) Run Nos. (a/g) Bun Nos. 01 i 64G J Ok0.002 60A,D,E,G O 0.17 eference Reference Curve Reference Curve urve I P = i atm P = 1 atm = atm (a/g) = (a/g) =1 (a/g) = 1 a. (ag) < 0002,Satured b. (a) < 0.002 Subcooleda c. (a/g) = 0.17, Subcooled 101I I I I I i I -In -50 10 50 10 50 AT OF sat' Fig. 24. Effect of (a/g) ontransition boiling at three atmospheres.

81 105 _R R at 10 PReference Curve Reference Curve P = 1 atm P = 1 atm (a/g) = 1 (a/g) = 1 1" Dia. Sphere 1" Dia. Sphere P = 5 atm P = 5 atm Saturated Liquid Subcooled Liquid (270F-330F) (a/g) Run No. I (a/g) Run Nos. 1 1 O <0.002 77D,E 10.002 61E,F,G,H a. (a/g) < 0.002, Saturated b. (a/g) < 0.002, Subcooled 10 I I I I I I I 10 50 10 50 ATt, OF Tsat' Fig. 25. Effect of (a/g) on transition boiling at five atmospheres.

82 105 R i 10 a-1 Reference Curve Reference Curve P = 1 atm P = 1 atm (a/g) = 1 (a/g) = 1 1" Dia. Sphere 1" Dia. Sphere P =5 amP 5 atm P t 5 atedm Lid Subcooled Liquid Saturated Liquid (220F) (a/g) Run No. (a/g) Run No. @1 01. 77H 641 0 0.17 0 0.17 10:L I I I / I I I I I I I I 103 L c. ( a/g ) = 0. 17 Saturated l l d. ((a/) = 0.17, Subcooled 10 50 10 50 AT 0F sat' Fig. 25 (Concluded)

and (ATsat)max (the ATsat at which peak heat flux occurs) at values of (a/g) < 1 when initiated by a change from transition boiling at (a/g) = 1. The values of heat flux for a given ATsat at (a/g) < 1 are less than the values of heat flux at (a/g) = 1 by as much as an order of magnitude, but specific decreases cannot be predicted. The results of Merte, et al., 9 for the 1-inch diameter sphere at 1 atmosphere and (a/g) < 1 (Fig. 23) led to the same conclusions. c. Peak Heat Flux Boiling The effect of pressure on the value of the peak heat flux, (q/A)max, is shown in Fig. 26a for saturated liquids at pressure of 1, 3, and 5 atmospheres. For any particular test run, only those data in the vicinity of the peak heat flux are shown. An increase in heat flux with increasing pressure is evident, There does not appear to be any clear influence of pressure on the ATsat at which the peak occurs, (ATsat)max. The effects of subcooled boiling on (q/A)max are shown in Fig. 26a for pressures of 3 and 5 atmospheres. A definite increase in the value of (q/A)max is observed when subcooling is present, but again there is no trend of ATsat at which the peak occurs. The effects of (a/g) on peak heat flux is shown in Fig. 26b for saturated boiling at 5 atmospheres. A decrease in (a/g) is accompanied by a decrease in the peak heat flux and a slight decrease in the ATsat at which it occurs. The results of Merte, et al.,19 for the 1-inch diameter sphere at 1 atmosphere showed (q/A)max decreasing with decreasing (a/g), as shown in Fig. 26b. A decrease in (q/A)max with decreasing (a/g) was also observed

105 s.P = 5 atm (a/g)=l. Saturated Liquid P =5 at sa|f. P = 3 atm sub. (a/g)=O.l P=atm CM 1a/g|<0.002 Refefence Reference Curve Curve 0 Cre P: I I Curve I I II I ~ P = 1 atm Saturated ( =1 Liquid 1-inch Diameter Sphere P,atm Symbols Run Numbers l04 a/g 1.0 0.17 <0.002 1.0 0.17 <0.002 P atm 1 Saturated V Ref. 19 0.01<(a/g)<0.03 -3 Saturated 0 73C Ref. 19 3 Saturated A 57D 3 — Saturated A 57D~~~~~~~~~ ~ 1-inch Diameter Sphere 5 Saturated O O U 73B 77H 77E a. Effects of Pressure 5 Subcooled (270) O 571 and Subcooling b. Effect of (a/g) I I I I I i II I I I I I I I a I I I I I! I I I 10 70 10 100 AT 0F sat' Fig. 26. Effects of pressure, subcooling, and (a/g) on (q/A)max

85 with suibcooled boiling (e.g., Test Runs Nos. 60D, G, 61E, F, 64G, I). d. Nucleate Boiling Representative examples of the (q/A) vs. ATsat data for nucleate boiling on a 1-inch diameter sphere are presented in Fig. 27. The effects of pressure on saturated nucleate boiling are shown. Except for the pressure-induced differences near the peak heat flux region, the nucleate'boiling curves at a given heat flux differ from the reference curve by less than 20F. Comparable variations were found in the nucleate'boiling curves obtained for different test runs at the same pressure of 1 atmosphere, and the results presented here should not necessarily be interpreted as indicating any effect of pressure on saturated nucleate'boiling over the range investigated. A larger variation in the experimental ATsat for a given (q/A) was found with subcooled liquid,'but no consistent trend could be noted. Typical results of nucleate boiling with reduction in (a/g) are shown in Fig. 28. The last data point obtained at (a/g) = 1 prior to the release of the test package is designated on the figure'by an "R " There is no apparent influence of (a/g) on nucleate boiling either with a saturated liquid, as shown, or with subcooled liquids, not shown (e.g., in Test Runs Nos. 60C, F, 61E, G, H, 64G, I, K). e. Natural Convection The heat transfer regions of prime interest in this study were those associated with boiling. Operations with subcooled liquids made it poss:i'ble in some cases to make measurements i.th non'boiing naturall convection taking place. The (q/A) vs. (Ts-Tge) data obtained are presented i.n Fig. 29.

5 10 P, atm Run Number o i saturated Ref. 19 o 3 saturated 73C * 3 subcooled 160F 57D 5 saturated 73B ~ 5 subcooled 220F, 250F 64 K, 56 H Reference Reference Curve Curve Saturated Liquid - 4 10 4-, 1-inch Diameter 1-inch Diameter Sphere Sphere Subcooled Liquid Saturated Liquid (a/g) = 1 (a/g) =1 103 1 10 30 10 30. AT OF ssat' Fig. 27. Effects of' pressure and subcooling on nucleate boiling.

87 105 a/g Run Number _ * 1.0 73C -O 0.17 771 O <0.002 77G 1-inch Diameter Sphere Reference Curve A s P = 1 atm 10 1 10 30 AT OF Fig. 28. Effect of (a/g) on saturated nucleate boiling.

88 10 P,atm Subcooling, OF Run Number 0 3 150 57E 0 5 250 57J 1-inch Diameter Sphere (a/g) = 1 CM & _ O 0/ 02I0 1 10 30 (T sT9, OF Fig. 29. Effect of pressure on free convection.

89 There is no effect due to either pressure or degree of subcooling. No data in this region were obtained for (a/g) less than 1. 3. Photographic Results for Film Boiling The results of film boiling from the disk presented in Fig. 16 did not show any influence of orientation on the process, at standard gravity. Work done by Class, et al.,36 has shown a definite sensitivity to orientation (orientations used were: vertical, 45~ heating up, and horizontal heating up) for film boiling of hydrogen on a 22-inch long strip, although the data of Heath and Costello,35 with film boiling at high gravity, did not indicate a sensitivity to orientation. It was intuitively felt that at least the adverse effect of the body force in the horizontal orientation facing downward should give rise to distinct effects, but this was not the case. In an effort to determine if the lack of any significant effect could be related to the thickness of the vapor film, a series of high-speed motion pictures were taken to attempt measurements of the vapor film thickness. The liquid used was saturated liquid nitrogen at 1 atmosphere and all photographs were taken at (a/g) = 1 The disk was positioned in the vertical, horizontal heating up, and horizontal heating down positions. The 1-inch diameter sphere was also photographed to provide information on the effect of geometry on the appearance of film boiling. Representative composite tracing of several frames for each condition, at various values of ATsat, are presented in' each of Figs~ 30, 31, 32, and 33 for the different orientations and configurations. The measurements of

- L.100" Saturated Liquid | g,' II - FAiT =000F AT =000F AT ~300F sat sat at 1" Dia 1" Dia 1" Dia Sphere Sphere Sphere.100" Saturated Liquid g P = 1 atm (a/g) = 1 Fig. 30. Composite tracings of photographs of film boiling on a sphere.

91 /~~I / 41 II 41 54~~~~~1~~5 212I, 31 31 21 4/ / ii ~~~~~~~~31 / 1 4151 41 iI 512 31 41 31 / 31 / h 51' / AT sat 100 OF AT t 2000F 31 AT 300 OF 31 / /,// sat 21 21 31 hi 51~~~~~~~1 3" Dia. Disk 351?'Da1 21 313" Di i aw> 0I31 31 Dia Disk 51 Disk 21 341~~~ ~13 21 51 II 100I iI~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~1 21 51 51 211 h1 021 41 1 31 sI 31 (a/g) 1 ~31~ ~21 51 F:I. Cm'h i i / / Fig. 51. Composite tracings of' photographs of' film boiling on a vertical disk.

3" Dia. isk Avg. 4 4 1 5 3 03 2 5 L4 2 5 2 1 2 T = 100 OF 3" Dia. /sat // 3" Dia. Disk A.vg. 2 2 1 3 3 sat |// /// / I 3" Dia. Disk 2 4 1 3 4 2 — Avg- 7- -2- 3 4 sat 300 OF 0 // (a/g) on a horizontal disk heating up.

C/ / 2/ Avg. 34 2 51 5 4 3 /1 5 4 3 2 1 4 3 2 1 5 4 3 25.044"/ 3" Dia. Disk Avg. 2 1 3 4 5 5 2 1 3 5 2 5 2 134 5 4 2 1 3.042" 3" Dia. Disk /at; 300 OF Avg. 5 6 4 3 2 1 6 5 4 3 2 1 6 5 4 3 2 6 1 5 4 3 2 1 6 5 4 3 2 I.100" 1 3" Dia. | 9 Saturated Liquid Disk P =1 atm (a/g) = 1 Fig. 33. Composite tracings of photographs of film boiling on a horizontal disk heating down.

94 vap~or film rthickness correspondinlg to thuse shwn.n the composite tracings are tabulated in Appendix A.3. Selected film frames corresponding to those presented in the figures are included in Appendix A.2. The frames at each ATsat were spliced into continuous strips for viewing with a 16 mm projector. Where appropriate, the results of visual examination of the boiling process (while the movies were being taken) are also indicated. The viewing angle used for the disk, parallel to the heating surface, gives the maximum film thickness across the entire face of the disk being observed. Any localized disturbance in the flow pattern at any point on the disk surface would result in the thickest film at that position being photographed. Therefore, the measured film thickness establishes only an upper limit for the local dimension, and does not represent the mean film thickness. The use of a composite of observations permits a more accurate assessment of a mean film thickness than a single frame would. This is not a problem for photographs of the sphere for obvious geometrical reasons. a. One-Inch Sphere Film boiling on the 1-inch diameter sphere, as shown in Fig. 30, is characterized by a thin film on the bottom and sides of the sphere. The film is attached to the sphere up to about 60~ from the top of the sphere, then becomes much thicker and quantities of vapor detach from the surface. At ATsat = 200~F, small waves can be identified on the lower hemisphere, and'become quite prominent on the upper hemisphere below the point at which the vapor clearly separates from the sphere. At ATsat = 300~F waves are vEisible over almost the entire surface of the sphere. The area on the top

95 of the sphere from which the vapor leaves, forming a column, does not change significantly over the range of ATsat examined. The diameter of the column appears to increase with increasing ATsat, as might'be expected for the larger mass flow rate of vapor which occurs at larger ATsat. Visual observations made while the film was being taken revealed that the vapor column did not appear as axisymmetrical bubbles released at intervals. A continuous slug of vapor appeared to tear away from the sphere in a helical fashion, with the center of the area of detachment describing a circle about the vertical axis of the sphere. This phenomenon was most pronounced at the highest level of ATsat usedo It may be seen in Fig. A-1 in Appendix A.2 where it appears as a displacement of the vapor column from the vertical axis of the sphere as a function of height above the sphere (and therefore as a function of the time of release of vapor from the sphere). Photographs taken'by Frederking42 show a similar phenomenon. b. Vertical Disk The composite tracings of the film thickness observed on the vertical disk are shown in Fig. 31. Each frame in the sequence used was identified with a number. These numbers are placed beside the lines indicating the vapor-liquid interface on each frame, and show the variation in interface position at approximately OoOOl-second intervals. The vertical disk does not present the same configuration to the boiling liquid as a vertical flat plate with a horizontal leading edge (i.eo, a two-dimensional leading edge is present). The vapor film on the disk appears similar to that anticipated for a vertical plate. The film near

96 the leading edge is initially thin, with a fairly well defined transition to a greater thickness evident at a location below the centerline of the disk. The lower portion of the vapor film does not appear to show any significant change in thickness with an increase in ATsat over the temperature range covered here. The solid-interface spacing in the upper portion of the vapor film is greater at ATsat of 2000F and 300'F than at 1000F. An increase in the number and magnitude of localized disturbances with increasing ATsat was observed visually while the films were being taken. These disturbances appeared in the form of waves and'bubbles. The bubbles separated from the film layer and moved upwards i.n a path parallel to the vapor film. The waves, which are also represented in Fig. 31 as localized thickenings of the film, moved upwards without actually detaching from the film. The increasing prevalence of these disturbances can'be seen quite clearly in Fig. A-2 of Appendix A,2. c. Horizontal Disk Heating Up In order to observe the film'bo:.l.ng process taking place at the top of the disk without having the view obscured'by the vapor flowing from the'bottom and sides of the disk, it was necessary to attach a collar which diverted the flow of vapor from the bottom and s:ides of the heater to the side of the field of view. While this technique may have had local effects at the edges of the disk, it is felt that the film boiling in the central portions of the disk was substantially unaffected.

97 Film thickness composites for the horizontal disk heating up are shown in Fig~ 32. At ATsat = 1000F the measured thickness of the vapor film above the heating surface was nearly constant. No measurements were taken where'bubbles were forming or leaving the surface. At higher values of ATsat the thickness and irregularity of the film increases drastically. Comparison with the film frames in Fig. A-3 of Appendix A.2 indicates that at ATsat = 100'F the number and frequency of bubbles released is relatively low. Large individual bubbles may be clearly distinguished after departure from the vapor film area. At ATSat = 200~F, the frequency and number of bubbles has increased with relatively little change in the size of the bubbles and the vapor film has increased in thickness. At ATsat = 3000F the spacing between departing vapor bubbles appears to be smaller, indicating that the frequency of bubble departure has increased further. A consequence is that the vapor film thickness appears to be only 2/3 of what it was at ATsat = 2000F. At the two higher levels of ATsat the increased bubble frequency make it extremely difficult to obtain a measurement of either an average or minimum film thickness. This is indicated by the extreme variation in film thickness as shown in the composites of Fig. 32. The average film thickness obtained from the composites is indicated, but is probably a maximum value rather than a true average. Visual observations made while the photographs were being taken revealed that, after detachment, the individual bubbles moved upwards very slowly. There was little mixing or coalescence of these bubbles. The physical size of bubbles ranges up to 1/2 inch major dimension, with the bubbles

98 showing a slight increase in size with increasing ATsat. d. Horizontal Disk Heating Down Observation of the vapor film on the disk surface in the heating down orientation is not obscured'by release of the vapor generated, as it flows up and around the sides of the disk, and therefore away from the interface being examined. Inspection of Fig. 33 shows that the composite interface at each ATsat is much smoother in appearance than those for the other orientations. It might be anticipated that the film thickness would increase with increasing ATsat'because of the higher heat flux. This generates more vapor, which should result in a thicker vapor film owing to the increased'buoyant forces necessary for removal of the vapor. This is examined in detail in Appendix B. No difference could'be discerned in film thickness'between ATsat = 1000F and ATsat = 2000F, while at ATsat = 3000F it increased'by approximately 50%o. Visual observations made while the film was being taken revealed a number of waves and protrusions appearing sporad:.cally on the vapor-liquid interface~ The protrusions, which. can'be seen in Fig. A-4 of Appendix Ao2, generally appeared.'briefly, then subsided'back into the interface. The waves could'be observed moving across the surface of the disk for a considerable distance before either disappearing or going past the edge of the disk and being absorbed in the upward flow of vapor. The overall effect was one of continuous motion, in'both horizontal and vertical planes, of the vapor-liquid interface.

99 The mean values of the vapor film thickness for the horizontal disks, along with an estimate of the maximum deviation, are listed in Table II. TABLE II MEAN VAPOR FILM THICKNESS (inch) 3-inch diameter disk, P = 1 atm, (a/g) = 1, saturated liquid Disk ATsat Orientation 1000F 200~F 300~F Horizontal heating up 0.035 ~ 0.020 0.124 ~ 0.020 0.080 ~ 0.020 Horizontal heating down 0.044 ~ 0.010 0.042 ~ 0.010 o.0o60 0.O10 4. Anomalous Results The measured heat flux in film boiling at a given ATsat for a particular set of conditions (geometry, pressure, etc.) could normally be repeated to within ~355%, and in many cases it could be repeated to within ~10%. In a few cases involving film boiling on a disk, deviations from the average values of (q/A) at a given ATsat of from 50% to 500% were observed. In one case such a deviant run was duplicated within a few percent at (a/g) = 1 and 0.16. These anomalous data are shown in Fig. 34. Anomalous results were obtained for'both saturated and subcooled liquid, and for the disk in both vertical and horizontal heating up orientations. These results could indicate an incipient instability in the liquid-vapor interface on a flat plate which occasionally is maniffested as a substantial reduction in the thickness of the vapor film. Normally such an effect may

105 Liquid Disk (a/g) Run P,atm Condition Orientation 1.0 0.16 <0.002 Numbers 3 Saturated V 0 0 68 I, 75 J,K 5 Saturated HU O0 71 I 5 Subcooled HU O 71 L 5 Subcooled V & 66 F Eq. (25) P = 5 atm 4k~~~~~~~~~~~~~~~ ~ t Eq. (253 P =3 atm a & — inch Di ameter Sphere 103 + Eq. (25) P = 5 atml 1 50 100 100 AT sat' F Fig. 34. Anomalous film boiling.

101 tend to be damped out or localized, being evidenced only by a relatively large variation in values when attempts are made to repeat particular results. Hosler and Westwater43 obtained variations of almost 100% from their average curve on a few runs with film boiling of water at atmospheric pressure on an 8-inch x 8-inch horizontal flat plate. Further speculation on possible causes for the results observed is not warranted at this time. The possibility of investigating the phenomenon in detail is intriguing.

CHAPTER VII DISCUSSION AND ANALYSIS Many correlations have been proposed for the various boiling regimes in attempts to fit or describe the various published data. The data for liquid nitrogen are largely summarized by Fig. 35, which has been reproduced from Ref. 44~ The correlations are discussed'by Seader, et alo 44 who show that no correlation has'been advanced which fits all of the experimental data in any single boiling regime. This is anticipated in lig1ht of Fig. 35, where the nonreproducibility of results is most likely due to the nonuniformity of the significant parameters, some known and others as yet unknown. A variety of materials, test surfaces, and orientations were used in obtaining the data presented. The objectives of this study were to determine the effects of varying test surface configuration and orientation on boiling heat transfer, along with variations of gravity field, system pressure, and subcooling. Discussion and analysis of the experimental results of the previous section are presented below in the order of film boiling, minimum heat flux, peak heat flux, nucleate boiling, and free convection, i.e., following the course of the cooling curve used to obtain the data. A. FILM BOILING Saturated Liquid Boiling Correlations Frederking and Clark31 correlated the film boiling data obtained by 102

10 AL.,IkL' ) ] (4) olereo. t.a. e* Cmn vochirol. ~.l Clark, et.l. 3 rleuter 1VP (26 n.m et.a. I (53 erit. st.al. Cl l 36~ v24.o, *1.1d. Ut (Ib wkel.de. et.al.. Tf (42 a.. *aa. IT (45 Iyou 3wOm 146 Ly. t.el. 3' / 5 60 3eake, VIT,.~ 5 Ub~~~r 10 well W 69 Well. eot.ol. S. CmW ( we ei, it.al. W __________ _ 2(58)20 ct~~~~~~~4 i,~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~u Cm 4-; YI //1 \ / ('1 4 10 +i i3'(46)'. i \ (46) 61 (52),1' 7~~~~~~~~~~~~~~~.9 (24) 5o,i~,-. (52) P z. Nmbe a orN in peathem r~fer to Referee numbs. Otber number refer to oasttie 2prrar ar aoiao 13 (24) r. Insur (-9 a 3rLat. 10~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~3 31.6.1rnr~bm ~1 lO.9 3 3. Dhsd lime. refe1r to traanit.( regi2m. 4. Circles refer to measured valums of maz uB aweleak) kboilag hlwt nw. saortontal u F g 5ori5metal piuoe Viiortmontal. Plate VPertical FLetoe ~'9 ~ -(69} IV VT Vertical Vi? 3 Sphere M naions~ 10 2 0.1 1.0 10 100 1000 10DO0 AT OF sat' Fig. 35. Experimental pool boiling data for nitrogen.

104 Merte, et alo,19 for a sphere by using the Nusselt (Nu) and modified Ray'leigh (Ra ) numbers. The relationship obtained was: Nu = Cl(Ra )1/3 (16) where Nu hD (17) kvf and Ra' = D PVf(PPvf) (.vf hfg + (18) (4vf k vf TtCpTsat with C1 = 0.14. The correlation was developed on the basis of data from film boiling of saturated liquid nitrogen at atmospheric pressure and standard gravity only. The film boiling results obtained with saturated liquids at pressure of 1, 3, and 5 atmospheres for the 1-inch, 1/2-inch, and 1/4-inch diameter spheres and for the various levels of (a/g) are plotted on Fig. 36 in tens of Nu and Ra'. The Frederking-Clark correlation is also shown and except for the results with the 1/4-inch diameter sphere correlates the data quite well, including the vari.ations in pressure and. (a/g). For a given Ra', the Nu for the 1/2-inch diameter sphere is approximately 7/ higher, and for the 1/4-inch diameter sphere approximately 20% higher than that corresponding for the 1-inch diameter sphere. If the constant C, is evaluated independently for each diameter, values of 0.14, 0.15, and 0o17 are obtained for the 1-inch, 1/2-inch, and 1/4-inch diameter spheres, respectively. C1 may

P, Atmospheres 1 3 5 Sphere a 13 Diamete - 10 Q~~~~10 0 i.o 0.6 1 I $.0.33 0 0.17 0 U 1/2.0 or AC - - 102 Q d, 999~~9 lo2 _ _ 9 ~/~.~ 14 0 Correlation of Frederking and Clark (Ref. 31): Nu = 0.14(Ra')1/3 Nu = k _ D3 pvf(pz-pvf)g C hf vf Ra' = --— + 0f5)(a 2 k CAT g (Pvf) vf p sat l7.8 9 1010 1011 O12 10 10 10 01 Ra' Fig. 36. Correlation of saturated film boiling on spheres.

106'be related to the diameter by: 1/8 C = 0.14 (Dre (19) where Dref, the reference diameter, is chosen to be that of the 1-inch diameter sphere for which the correlation was originally developed. Manson and Seader45 obtained (q/A) vs. ATsat film boiling data for a 4-inch diameter sphere in saturated liquid nitrogen at 1 atmosphere and (a/g) = 1. They reported that, for a given ATsat, their (q/A) results were approximately 10% lower than those of Merte, et alo19 The decrease in heat flux between a 1-inch and 4-inch diameter sphere predicted by Eqs. (16) and (19) is 16%., Equations (16) and (19) are thus shown to be applicable with sphere diameters varying by a factor of 16 and Ra' covering a range of 4 orders of magnitude. The saturated film'boiling data obtained with the spheres are replotted as Nu vs. [Rae x (D/Dref)-3/8] in Fig. 37. Also included are the data for film boiling of Freon-113 from a cylinder over the range 1 < (a/g)< 10, and Bromley's correlation27 for laminar flow film boiling from a horizontal cylinder. Bromley's correlation for the heat transfer coefficient, h, in film boiling from cylinders'7 is = 0.62 vfP Pv f)hfg] (20) L vfATsatD With the exception of some of the 1/4-inch diameter sphere results at (a/g) = 0.17, Eqs. (16) and (19) fit the experimental data within +25%. The diameter of the test cylinders used by Pomerantz,4 0.188 inch, was

LN DATA (SPHERE) FREON 113 DATA 2 (CYLINDER) Modified Frederking-Clark (Nef. 31) Correlation: u 1/3 D P (atm) ___ 1 3 5 POMERANTZ (Ref. 34) ref Sphere a/g j I Approximate Curve Fit Through Manson-Seader (Nef. 45) Dim. (in) 1.0 o o a Data for 4-Inch Diameter Sphere in LN2 0.6 0 1 0.336 LL.2.J 3 0.2 0 4 V 10 1 0.17 m A 1/2 11.0 d 7 + 1.0 9 91 4 1 1/4 [0-17 9 9 O D = 0.1875 inch ref 2~~~~~~~~~~~~~~~~~~~~~~~ 10~~~~~~~~~~~~~~~~~~~~~~ Bromley (Ref. 27) Correlation for Laminar Flow (using 1. inch ref D P,(P P )g P h f 107 10 1010 11 Fg3.CrlinfsuaD Nu~~~~~e Fi.3.Crrlto fsauae il oln n pee ndclnes

1o8 used as the reference diameter for the cylinder data. The saturated film boiling results obtained using the disk were also plotted as Nu vs. Rav in an attempt to determine if this data would be correlated by the same parameters as were the data from the sphere. The plot for the vertical disk is shown in Fig. 38. The value of D used in Fig. 38 was the disk diameter, 3 inches. A straight line fit through the (a/g) = 1 data on Fig. 38 can be used to predict most of the experimental points within ~25%. The data points for (a/g) = 0o16 deviate considerably from such a fit, indicating that a correlation of the form Nu = C1(Ra' )n does not properly describe the film boiling process for the disk in this case. This was also true for other orientations of the disk. Other investigators (Refs. 34, 43, 46, 47) indicate the appropriate dimensions for correlating film'boiling data from a flat surface may be what are referred to as the critical wavelength, Xc, and the most dangerous wavelength, Xd. The heat flux of a flat plate heating upward should not be influenced by its physical dimensions at a given ATsat provided the plate is large enough to neglect edge effects. It is possible that changes in properties or other relevant parameters which influence the vapor film thickness and vapor flow patterns, and there-'by influence the heat flux, may be reflected in changes of Xc and Xd. Bellman and Pennington48 showed that the smallest wave which will'be unstable along a vapor-liquid interface, in an adverse gravity direction, has a length, called the critical wavelength, given'by

10 P atm 1 3 5 a 1.0 O 0 a _ [ 1.0 | 1 | A 3-inch Diameter Disk O Vertical Orientation O 3 " O0 10 —:~~ r ~~~~Straight Line Fit Through (a/g) = 1. Points Nu = hD 2 k ol wCAT g 102 1010 1011 Ra' Fig. 38. Correlation of saturated film boiling on a disk.

110 Xc = 2rrg g0, 1/2 -1/2 When the wavelength is shorter than Xc, the interface is stable, and disturbances will'be damped out. When the wavelength is longer than Xc, the interface is unstable, and disturbances will grow. In the case of film boiling, this implies that if the wavelength is longer than Xc, bubbles will form and detach from the vapor film, while if the wavelength is shorter than Xc, interface motion may'be observed but no bubbles will form. Bellman and Pennington48 also showed that the rate at which a disturbance grew was a function of the wavelength. The wavelength for which the amplitude of a disturbance grows most rapidly is called the most dangerous wavelength, given'by Xd = 2 g0 1/ - Ia (22) The critical wavelength increases with decreasing (a/g), indicating that for film boiling at very low values of (a/g) there is no hydrodynamic justification for the formation of'bubbles as such. The analysis is based. on the existence of a vapor-liquid interface with an adverse gravity direction (Taylor instability) so extension of the analysis to true zero gravity conditions is meaningless. The critical wavelength, Xc, was substituted for the characteristic dimension D in Eqs. (17) and (18) to determine whether it might be a more appropriate characteristic dimension for the horizontal flat surfaces. The exponent on (a/g) in Rag was changed from 1 to 2/3 to reflect the ex

111 perimentally observed decreased sensitivity of (q/A) to changes in (a/g) at a given ATsat. The disk data were thus expressed in terms of parameters designated by Nu" and Ra", where hkc Nu" -C (23) kvf ha 2Pf(PZ -Pf)g (C 2psa + 0 )ca)/3 (24) Ra " -- -I )2 (241 \ k /vf \CpATsat The results are shown in Figs. 39, 40, and 41 for the disk in the vertical, horizontal heating up, and horizontal heating down orientations, respectively. The disk data for all orientations, pressures, and values of (a/g) = 1 and 0.16 may be represented with an accuracy of ~35% by the relation ship Nu" = 0.012 (Ra") /2 (25) Hosler and Westwater43 measured heat flux as a function of ATsat for saturated film boiling on an 8-inch square horizontal, heating up, flat plate at atmospheric pressure using water and Freon-ll (CC13F) as test fluids. Representative points from these results are also included in Figs. 40 and 42. They fall about 40 to 60% below the disk data at the same value of Ra". If the'boiling phenomena were identical (i.e., solely a function of Xc) regardless of plate size, the data might be expected to agree. Berenson5 analyzed film boiling from a horizontal flat surface heating up and developed a correlation for the heat transfer coefficient,

10o3 a/g-' 1.0 0.16 P, atm 3 O 5 A I 3-inch Diameter Disk O ~ Liquid Nitrogen E O K Nu" = 0. 012 (Ra") |~~~~~~~~~~~~~~- gl1/2( 1/2 ( ) 102 27r hg0 a (a) -1/2 1 1Null 1l2 ll 87r3 9 f 1/2 a3/2 C h Ra" = vf/ (k) ( f + 0.5)(g) 1/2v 1/2 k C2 AT (P. Pf gP vf p sat 107 1o8 10 10 Ra" Fig. 39. Saturated film boiling correlation for a vertical disk.

10 Nitrogen Water Freon-l1 Test Surface 3" Dia. Disk 88 x 8" x 8" IFP* a/g 1.0 0.16 1.0 1.0 P, atm 00V 5 *(Ref. 43) Eq. (26), Ref. 3 1/2 ~ Nu" = 0.012(Ra") H 00 O O 2irh 1/2 01/2 -1/2 0 Nu" k /2 1/2' kvf 9 (p Cp Vf 3 1/2 3/2 Rat' = 87_____f_______ _ hg + 0-5) -p )1/2( k C T g Mo to k vf k p sat 7 ~~~~~~~~~~8 9 t 107 10 10 10 Ra" Fig. 40. Saturated film boiling correlation for a horizontal disk heating up.

10 a/g 1.0 o.16 A 1 0 () Pa 3-inch Diameter Disk Liquid Nitrogen 102 00 1/2 2 3/2 h (p -p 1/2 2 1/2 k AT s 107 108 101 Rall Fig. 41. Saturated film boiling correlation for a horizontal disk heating down.

TFlid I Nitrogen, Water Freon-li Te"tDia. DisK 818 F. P.ic 8i8'tF.P* Ovitntmt veriticadl oriz. Horz. i. Hori. V@ctI MQ P eat Down A4.at,. u imt.p up 2. l H 10 o or 0 / 3 *~~~~~~~~~~Ref. 43 1/2 1 Nu" 0.012(Ra") dRa 00 0 10 0 /2 1/ "~ ~~~~~~'t O 271~~~~~~~~~~~~~ hg~vtg1/2 (P-r 1/2 a \ Eq. (26), Ref. 3 3 P g1/2 03/2 hfg 0.5) Rail 87T f g 0CP hf + 0 -5) (a) 5/ 1/2 2 (f) C AT + Pkpv (p)2 g1/2 vf p s-at 7 ~~~~~~~~~~~8 9 i 10 10 10 t1 Ra" Fig. 42. Saturated film boiling correlation for flat plates.

l16 r i =e 0 [425/g J1/4a)/8 (26) LJv, J(P -Pv) This correlation, developed for a plate of infinite extent, is included in Figs. 40 and 42, and predicts a'behavior considerably different from that of this study. This may indicate that a size effect, such as the one given for the spheres in Eq. (19), is also present with flat plates. The difference in slope'between the correlation of Berenson3 (1/4) and the experimental data (1/2) may indicate that laminar conditions do not exist in the present experimental conditions. This is discussed further in Section VII. A.3.e. The calculated value of kc at (a/g) = 01'7 is more than twice the d.iameter of the 1/4-inch diameter sphere at all pressures,'but is less than the diameter of the 1-inch diameter sphere. Breen and Westwater49 orbserved a change in hydrodyrnamic'behavior, from a two-di.mensional wave pattern to a one-dimensional wave pattern (Pomera:ntz34 considered these as tlhreedimensional and two-dimensional -wave patterns, respectively) when cylinder dimensions were decreased from greater than kd to less than kc. Adopting Pomerantz? terms, a two-dimensional wave pattern:is characterized'by flow of the vapor around a cyl:.nder or sphere to the very top, wh.ere it is released from a narrow slit along the top of the cylinder or a narrow tube at the top of the sp'here. A three-dimensional wave pattern is characterized. by'bubbles leaving t'he etire top half of the ctrele nder or sphere at many d:fferent circinfere rnt~i.al positions. If the three -d:imens~i.o:nal wave pattern

117 on the 1/4-inch diameter sphere at (a/g) = 1 changed to a two-dimensional wave pattern at (a/g) = 0.17, the characteristic dimension for use in the correlations might well be Xc rather than the sphere diameter. The test facility did not permit examination of the wave patterns on a test object during package drop. If the change from a three-dimensional to a twodimensional wave pattern with the 1/4-inch diameter sphere results in an increased heat flux for a given ATsat, similar to that observed on the disk, then a reduced effect of (a/g) should also be observed and the exponent, n, on (a/g)n in (Ra') should be reduced from 1 to 2/3. The results obtained with the 1/4-inch diameter sphere at (a/g) = 0.17 are plotted in terms of Nu vs.[Ra'x (D/Dref) 3/8] on Fig. 43 using n = 1 and 2/3. The points plotted using n = 1 correspond to those shown in Fig. 37. The points plotted using n = 2/3 very closely approximate the correlation used for all of the other sphere results. Saturated film boiling appears to be governed by a number of factors in addition to the physical properties of the liquid and the temperature difference. Among these are geometry and orientation of the heater surface, which influence the hydrodynamic behavior of the liquid-vapor interface. Changes in the applied gravitational field also affect film boiling and these factors must all be taken into account if a single correlation for saturated film boiling is the desired result. A composite of correlations for boiling under saturated conditions in the various regimes is presented in Fig. 44. The reference curve, introduced in Chapter VI as applying to the 1-inch diameter sphere at atmos

P, atmospheres n 1 3 5 1. U * 2/3 0 O 102 1/N-inch Diameter Sphere 1 _ (a/g) = 0.17 _ Dref -1/8 Nu= 0.14(Ra')1/3 ( - Eqs. (16) and (19) ref Nu = hD RaNu = -- - vf D P f(P z=P )g C h Ral = f,2 k) (C AT -+ 0.5)(-) (if2 )vf p sat g vf 101 I I I I, 7 8 9 10 10 10 (Ra) (a)n-3/8 g Dref Fig. 43. Effect of exponent on (a/g) on a saturated film boiling correlation.

10a (q/A),, Eq. (51) Ref. 20 P = 5 atm, (a/g) = a P = 5 atm P = 3 atm, (a/g) =1 P = 3 atm P = 1 atm, (a/g) 1 (aTsat,c Eq. (54) Ref. 19 P = 1 atm, (a/g) <1 1i 1.0 1-inch Diameter Sphere o.6 r ~~~r 0.33;T~~t~~ 0.2 I!~~ = 0.1 / 7r~f Reference Curve P 1 atm (a/g) 1,A/~L~,, /tti.7I/ 0.03 (q/A) Eq. (44) Ref. 3 A, /r~~~~~lIS' ~~min 4-p I i/fI I1/71/ 0.00 rFiu Boiling ____;) CH 4~~~~~~~~~~~~~~~~~~~~~ 141 0// r P = 5 atm F: ~~~~~~~~~~~~~~~~/~00 P = 3 atm. 0f I~t'. -P Cc? Eq. ~~(16) Ref. J 1.0 0,~0 7 0.3 Nucleate Boiling0 0 Eq. (58) Ref. 11 l eI02/ I! 1,i, 1 0.6 -',' " 0.0 lo~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~o 10 10 3 0.03 II I 1 0~~ ~~.6 oe J# 0AT 3 00 F0 I // r ~~~~~0.2 - oe.0 0~l0 103 00 1 ~~~~~~~ ~~10 100 300 AIT OF sat' Fig. 44. Saturated boiling correlations.

120 pheric pressure and (a/g) = 1, is shown to provide a'basis for comparison. For saturated film boiling, Eq. (16) is shown, and the correlations for the other regions will'be discussed in the following sections. 2. Suibcooled Liquid Boilfng Correlations Suibcooled film boiling occurs when t'he'bulk liquid temperature is maintained below the liquid. saturation temperature. This is normally accomplished'by circulating the liquid, replacing the heated liquid'by cooler liquid. The resultant liquid motion along the:heated surface generally classifies subcooled film boiling as a forced convection problem (see, e.g., Ref. 50). Where film'boiling is to take place for relatively short periods of time only, as i.s present with the transient technique used here, it is possible to provide subcoolzing on a, batch basis, without the necessity for a circulating system, by pressurizing the system just prior to conducting the test. Ellion50O found experimentally t:hat, for a given ATsat, heat flux in the film'boiling region was larger with subcooled liquid than with saturated liquid. This had also been predicted analytically (e.g., Ref. 51 ). Sparrow and Cess52 studi.ed the problem of subcooled laminar filmboiling for the case of the isothermal vertical plate. The two-phase flow and heat transfer problem was formulated within th.e framewo-rk of'boundary layer theory, and a solution developed a'n expression for the local heat flux as _ 1/4 8( /p4p) g) 1/( q/A P.~ vf~vf ATsat ((2 2(LPvf)1/2 (x)l/4

121 The distance x is measured from the leading edge of the plate, and B is a computational parameter defined in Ref. 52 as a function of the thermodynamic and physical properties of the boiling liquid and the degree of subcooling. Equation (27) is plotted in Fig. 45 for liquid nitrogen at several different pressures and levels of subcooling in terms of (q/A) vs. ATsat. The height above the bottom edge of the plate, x, was taken as 0.125 foot which corresponds to the distance from the bottom of the vertical disk to the thermocouple position. The data obtained with the vertical disk at pressures of 3 and 5 atmospheres with subcooled liquid and at (a/g) = 1 are also shown in Fig. 45. For a given ATsat, the experimental levels of heat fluxes are approximately four times larger than that predicted by Eq. (27). The correlation for saturated boiling on the disk given in Eq. (25) is included in Fig. 45. To determine if the trend of the effect of subcooling as predicted by Eq. (27) is correct even if the absolute level is not, the ratio of the subcooled (q/A) (experimental data) to the saturated (q/A) (correlation) for various values of ATsat was calculated and is given in Table III. This ratio as predicted'by Eq. (27) is also given. The experimental results show an increase in the ratio (q/A)sc/(q/A)sat with increasing ATsat, while Eq. (27) predicts that this ratio will decrease with increasing ATsato

o Vertical Disk at 3 Atmospheres and a/g = 1, Subcooled o Vertical Disk at 5 Atmospheres and a/g = 1, Subcooled o Subcooling,0F Pressure atm 000 O ~~~0 - 5 4 -) 43 4-D4 P\ 0 009_ _ 0, / ~ ~ 0 Eq. (27) Ref. 52 10 I I I I I 11 A1 I 10 100 1000 AT tOF satF Fig. )45. Subcooled. film boiling correlation.

123 TABLE III COMPARISON OF ANALYTICAL PREDICTIONS AND EXPERIMENTAL RESULTS FOR THE RATIO (q/A)s,/(q/A)sat FOR A VERTICAL DISK AT 3 AND 5 ATMOSPHERES P. atm 3 5 ATsat, OF 100 200 300 100 200 300 Experimental Results 0.974 1.213 1.233 1.130 1.260 1.343 (subcooling, OF) (2) (8) (12) (10) (18) (20) Eq. (27) (Ref. 54) 1192 llO 1.067 1.302 1.140 1.098 (subcooling, OF) (15) (15) (15) (25) (25) (25) There are several possible reasons why the correlation of Sparrow and Cess,52 as given in Eq. (27), does not follows the experimental data obtained. First, the boiling film may have been turbulent, so a laminar film analysis does not apply. Second, the flow pattern over the disk may be sufficiently different from the flow over a vertical flat plate so the analysis does not apply. Examination of the photographic composites of the vertical disk (Fig. 31) indicates a thickening of the film near the thermocouple location, which may be an indication of the onset of turbulent flow. 3. Boiling Film Thickness Analyses The physical picture of film boiling is a superheated solid surface separated from a liquid by a vapor film. This may be compared with a picture of nucleate boiling where'bubbles form on a superheated solid surface, grow, and leave the surface. An exact mathematical model of the film boiling process probably cannot be formulated to include temporal variations in

124 the shape of the vapor liquid interface along with the departure of vapor'bubbles from the filmo It should be possible, however, to develop a model which approaches the actual phenomenon more closely than is possible in the nucleate boiling region. The physical appearance of the film was carefully examined in the composites presented in Figs. 30, 31, 32, and 33. The film around the 1-inch diameter sphere at (a/g) = 1 was not easily approximated'by a simple model. The film thickness on the disk in all three positions did not vary appreciably with time, and models were feasible. Models from the literature were used where available. Mathematical models were developed where required. Evaluation of the film thickness was the desired result. a. Film Formation at Zero Gravity A simple model of the vapor film i.s one in which there i.s no mass flux, which would exist in a true zero-gravity environment. If the liquid was in contact with the solid surface at time t = 0, the vapor film would form and continue to increase in thickness with increasing time. There would'be no convection in the absence of gravity, and if radiation is negligi'ble the problem is one of pure conduction. This problem has'been formulated'by Chang46 and more recently'by Yang53. The solution presented'by Yang takes into account finite values of thermal capacity and thermal conductivity of the solid surface and is presented here. This solution was developed for the transient condensation of a pressurizing gas in a suddenly pressurized cryogenic tank. The physical system analyzed consisted of a sem.i-infinite wall in the region

125 x < 0 and a semi-infinite body of phase 1 in the region x > 0. Initially the temperature of the system was uniform. At time t = 0 the temperature of the wall was changed and immediately phase 2 began to form on the wall. The temperature of the interface adjusts to the saturation temperature corresponding to the system pressure, and subsequently remains at that temperature. As applied to the problem of vapor film formation in a zerogravity environment, the solution for the film thickness may be expressed as = 2(Gct)l/2 (28) where ac must satisfy the transcendental algebraic equation: L (PCpk)1sd1 + erfF(c\ (PC pk) sd P C p(T Tsat) (a1 (pC V e ) I v erfc i (/...(PCp. = Pphfg(aoc) (29) c may be termed46 the equivalent thermal diffusivity in heat conduction through a substance with change of phase. Once ac has been obtained, (q/A) may be expressed as 2kvATsat q/A = 7 (30) as in Ref. 46.

126 The solution as applied to the problem presented here is a function of ATsat, pressure, and subcooling. For a given ATsat, pressure, and subcooling,film thickness is proportional to (t)l/2 and heat flux is proportional to (t)-1/2. b. Film Thickness on a Vertical Plate Film boiling heat transfer measurements were made using the disk in three orientations: vertical, horizontal heating up, and horizontal heating down. Film formation in a gravity field must'be treated separately for each orientation because the action of the buoyant forces in removal of the vapor generated is different in each case. The analysis of laminar subcooled film boiling on a vertical plate performed by Sparrow and Cess52 and discussed in Section VII.A.2 included development of an expression for film thickness. This was F l 442 1/4 -1/4 44Pvff Pvsa wheexise fm te l nge-Pdef gte h where x is measured from the leading edge of the plate. The parameter Trlv, which is a dimensionless boundary layer thickness, was evaluated by Sparrow and Cess52 as a function of the parameter B for Prv = 1l Hsu and Westwater30 performed an approximate analysis of the flow in a vapor film on a vertical plate. An expression was obtained for the height above the leading edge of a vert ical plate at wh ich the onset of turbulence could be anticipated. This distance was

127 _ vf(100)hfg6*.( 2) Lo -2) 2kvfATsat where 6*, the film thickness at the onset of turbulence, is = (L2f(100) (5)/3 gPvf (P I Pvf The value (100) appearing in Eqs. (32) and (33) represents the critical value of the flow Reynolds Number as given in Ref. 30, at which it is stated transition'between viscous and turbulent flow may be expected to occur. c. Film Thickness on a Horizontal Flat Plate, Heating Up Berenson3 obtained an equation for the heat transfer coefficient in film boiling from a horizontal flat plate heating upward (see Eq. (26)). An expression was developed for the average vapor film thickness for the entire surface, given as 2.35 L vfkvfATsat go 71/4 -3/8 (34).. L fgPvfg(Pf-Pvf) g(P-Pvf) The film'boiling model used consisted of a thin film of uniform thickness on which cylindrical bubbles with hemispherical caps were superimposed at regular intervals. Chang46 considered the film thickness to be dependent on the establishment of a stable wave motion wherein the buoyant and viscous forces are in an equilibrium condition. He obtained the value of this equilibrium film thickness to be jll, < 3( a -1/5 g(P'Pf~

128 where Ca must be evaluated from Eq. (29_). Comparisons between Eqs. (34) and (35) and experimental measurements are made in Section VII.A.3oe. d. Film Thickness on a Horizontal Flat Plate, Heating Down An analysis of the steady-state vapor film thickness below a horizontal flat plate heating down was made and is included as Appendix B. For the case of a disk with a parabolic velocity profile in the film, the solution giving the vapor film thickness is 6ly2y _ 2 2 _ = 3 (qA) ) 1 i (36) L hfg p Ppvfg where Y1 is the film thickness at the center of the disk, 61 is the difference in film thickness'between the center and the edge of the disk, and R is the radius of the disk, as shown in Fig. B-lo It is noted that both Y1 and, l are unknowns, and an estimate of one is required from other sources. e. Comparison of Vapor Film Thickness Analyses with Experimental Resuits The analysis presented for vapor film formation at zero gravity predicts that (q/A) will change with time. The experimental results obtained using the 1-inch diameter sphere and the second test package to obtain (a/g) < 0002 at 1 atmosphere saturated conditions exhibited such a temporal variation in heat flux. The drastic reduction in body forces reduced or removed the Taylor instability, changing the character of the film boiling process from a steady convective one no a transient conduction one.

129 These results were presented in Fig. 19 and are also shown in Fig. 46. Equations (28) and (30), developed for the flat plate under zero gravity, were evaluated for saturated film boiling of liquid nitrogen at a pressure of 1 atmosphere. The results obtained for heat flux and vapor film thickness at (a/g) O are shown in Fig. 47 for ATsat = 200~F. Also shown are the heat flux measurements from Run 52H at (a/g) = 1 and at (a/g) < 0.002, 0.7 second and 1.3 seconds after the package was released. Although Eq. (30) does not accurately predict the heat flux as a function of time, the predicted dependence of (q/A) on t-1/2 is shown to be fairly good for this run. The (q/A) calculated using Eq. (30) at t = 1.4 seconds is shown on Fig. 46 for a range of ATsat. Most of the experimental heat fluxes at 1.4 seconds are higher than those predicted by Eq. (30). The flat plate model should apply to the sphere in this case since the vapor film thickness predicted by Eq. (28) is less than 10% of the 1-inch diameter sphere radius even after 1.4 seconds. Equation (30) predicts that (q/A)oC (t)-1/2. The "early" data points shown in Fig. 46 were all obtained 0.7 second after the package was released. The "late" points were obtained 1.2 to 1.4 seconds after the package was released. Using these times for t in Eq. (30), predicted values of "late" (q/A) were calculated and are shown on Fig. 46. Reasonable comparisons are noted. In this region ((q/A) < 1000 Btu/hr-ft2) the value of dT/dt is less than 0.50F per second. The individual temperatures are read to ~0.20F,

130 10 O Experimental Data Obtained Early in Free Fall O Experimental Data Obtained Late in Free Fall - Predicted Value Late in Free Fall Assuming (q/A) a t-1/2 Reference Curve (a/g) =1 1-inch Diameter Sphere Saturated Liquid P =1 atm!103 l Eq. (30) at t = 1.4 sec for a flat plate Ref. 53 10 II I I I I l 40 100 400 AT OF sat' Fig. 46. Dependence of film boiling heat flux on time.

10401 (a/g) = 0 Saturated Liquid P = 1 atm AT 2000F 6,Eq. (28) Asat2 a 0.01517 ft /hr (from Eq. (29)) O Experimental Points, (a/g)<0.002, Run 52H -102 L I I I I I, I I I,,, I I,, I I,, 0-l/2;j 3 (q/A) a- 0.01 ~Q q/A, Eq. (30) 0.01 0.1 1.0 1.4 t,sec. Fig. 47. Variation of heat flux and vapor film thickness with time.

132 and for these runs readings were made every 0.1 second. Tangents were fit to the data points over a 0.4 second range (i.e., a change in temperature of 0.20F, which is equal to the reading error). An error of 0.10F in dT (estimated to be the maximum error for these runs) over this range is 0.25~F per second, which is an error of 50% or more in (q/A). The (t)-1/2 power dependence of (q/A) predicted for zero gravity appears supported by the experimental results. The photographic results obtained permit the film thickness to'be measured. The variables covered included test surface geometry, disk orientation, and ATsat. All photographs were taken using saturated liquid nitrogen at 1 atmosphere and at (a/g) = 1, so comparison of the predicted and observed film thickness is possible only under these conditions. The effects of (a/g), subcooling, and pressure on film thickness are predicted, but are not compared with experimental results. The equation for laminar vapor film thickness on a vertical plate obtained'by Sparrow and Cess52 (Eq. (31)) was evaluated for a value of x = 1.5 inches (the distance from the leading edge of the vertical disk to the point at which the thermocouple used for the temperature measurements was located). The results are shown in Fig. 48 as a function of ATsat. Experimental measurements obtained from Fig. 31 are also shown, and are approximately one order of magnitude larger than the predicted values. It should be recalled, however, that owing to the optical configuration used, the observed values of film thickness are most likely the maximum values across the surface.

4. to10 P, Atmospheres 0 Experimental Measurement 0 1 5 from Figure 31 at X = 1.5 Experimental Correlation Eq. (25) Eq. (31) at x = 1.5" Ref. 52 Eq. (37) Ref. 30 Eq. (33) using x from Vertical Disk Eq. (32) (x = 0.439" at AT = 1000F, x = 0.256" at P = 1 atm sat AT = 3000F); Ref. 30 (a/g) = 1 sat Cl) 00 Pq 1 C.) H Vertical Disk f U' P=l atm 4 / 0.0 Fs 10 (a/g) 1 a. Film Thickness b. Heat Flux 0io00 I I li i Ii I Ilo i I I I 11111 100 200 300 100 200 300 ATsat',FAsat) 0 Fig. ti8. Film thickness and heat flux in saturated. ~film boiling on a vertical disk.

134 The film thickness at which Hsu and Westwater30 (Eq. (33)) predict transition from laminar to turbulent flow is also shown in Fig. 48. It is seen to'be thinner than the thickness predicted by Eqo (31), and the x at which transition is predicted to occur is less than 1.5 inches. This implies that turbulent flow is present near the thermocouple location, and the analysis of Sparrow and Cess52 for laminar flow does not apply. Hsu and Westwater30 also predicted the turbulent heat flux on a vertical plate as a function of pressure and ATsat, obtaining q/A = kvf 3E (x-Lo) +(1 AT sat (37) where E = |(P Pv] L vf 12 (38) and fpvIvf (;100) kvfATsat Ptvf + F-_ =2Ovf hfg F (39) kvfATsat ihfg Equation (37) is included in Fig. 48 for saturated boiling at 1 and 5 atmospheres. Also shown i.s the experimentall correlation obtained in Section VII.A.l. (Eq. (25)),) The prediction is lower than the experimental curve by. 25% to 60o%, and shows a different slope for (q/A) vs. ATsat than was obtained experimentally. Although Eq, (37) does not accurately predict the experimental results,?it could be useful in obtaining an order of magnitude approximation to anticipated experimental heat fluxo The agreement of Eq. (37) to within 60% or less of experimental data,

135 coupled with the predicted location of the transition point being small, and the observed vapor film being an order of magnitude greater than a laminar flow analysis, all appear to indicate that turbulent flow may exist over a relatively large portion of the heater surface. An accurate determination of the location of the laminar to turbulent transition point along the vertical disk could be made by experimentally measuring the velocity profile in the film, but this would be a formidable task and was outside the scope of the project at this time. Examination of Fig. 31 does show more variation from frame to frame in the observed film thickness on the upper portion of the disk than on the lower portion. This could be indicative of turbulent flow, but no obvious transition point is apparent from examining Fig. 31. The variation in the observed film thickness from frame to frame is most pronounced at the highest ATsat = 3000F. The prediction of Berenson3 for the vapor film thickness on a horizontal flat plate heating up (Eq. (34)) has been evaluated for saturated liquid nitrogen at 1 atmosphere and (a/g) = 1. The results are plotted on 46 Fig. 49. The prediction of Chang for film thickness under the same conditions (Eq. (35)) is also shown. Experimental measurements obtained from Fig. 32 are presented. Berenson's prediction of film thickness is five times larger than Chang's prediction of film thickness at a given ATsat, but is an order of magnitude less than the experimental data. The models proposed by Berenson and Chang thus do not appear to follow the observed results.

136 O Experimental Measurement Figure 32 Eq. (34) Ref. 3 --—' Eq. (35) Ref. 46 O 0.1 —.~ O~O U) Cr 0.01 0.001 90 100 200 300 ATsat OF Fig. 49. Vapor film thickness in saturated film boiling on a horizontal disk heating up.

137 A comparison of Figs. 48 and 49 shows that the experimental vapor film thickness measurements are similar for the two disk orientations. The predicted thicknesses, although different from the observed thicknesses, are also similar. It has been shown on Fig. 16 that the (q/A) vs. ATsat results from the disk are similar for the two orientations. One might conclude then that the heat flux with film boiling can be directly related to the vapor film thickness. Chang54 has indicated that there should not be any significant difference between horizontal heaters and vertical heaters after the onset of turbulence. The film thickness on a vertical plate, as a consequence of turbulent motion, would thus be similar to that on a horizontal surface. Chang46 also stated that, for a small plate, the heat transfer coefficient for a horizontal plate heating down should be the same as that for a vertical plate. Flow along the vertical disk has been tentatively identified as turbulent over a portion of the disk. If the flow over the horizontal disk, heating up, is also turbulent, the proposed laminar models for the vapor film behavior would probably not apply. Chang's conclusion about similarity in heat transfer behavior between horizontal and vertical plates with turbulent flow would apply, and appears to'be supported by the experimental results observed here with regard both to film thickness and heat flux. The correlations for laminar flow predict film thicknesses in the vertical and horizontal heating up positions which are quite similar, and may indicate that the insensitivity of a flat plate to orientation holds in laminar flow as well. There is no experimental data available to examine this contention.

138 It has been pointed out (e.g., Ref. 1) that a similar lack of sensitivity to orientation exists for free convection heat transfer. In the turbulent regime, McAdamsl gives, for a horizontal plate heating up, Nu = 0.14 (Ra)l/3 (40) and for a vertical plate Nu = 0.13 (Ra)l/3 (41) a difference of approximately 8%. These equations are very similar in form to Eq. (16) for a sphere with saturated film boiling. McAdams also found a lack of sensitivity in the laminar regime. He gives, for a horizontal plate heating up, Nu = 0.54 (Ra)l/4 (42) and for a vertical plate Nu = 0.59 (Ra)l/4 (43) a difference of approximately 90)o, The predicted film appearance for a horizontal plate heating down may be obtained *by using Eq. (36)o The variation of 51 with Yl is shown in Fig. 50 as a function of ATsat. 51 and Y1 are defined in Fig. B-l1. For each ATsat the measured value of Y1 obtained from Fig. 33 is indicated. Predicted values of 65 range from 0.0041 to 0,011 inch. The value of YL was measured to ~0.010 inch. Variations in 61 of the range predicted

o Experimental Measurement from Figure 33 Prediction using Eq. (36) with Experimental Values of (q/A) Horizontal Disk, Heating Down P = 1 atm (a/g) =1 (q/A) = 66oo 9150 10470 Btu/hr-ft2 01 AT = 1000F 2000F 3000F 0.1 sat 0, 01 0.0001 0.001 0.01 61 = yl-Y2, inches Fig. 50. Vapor film thickuness variation in saturated film boiling on a horizontal disk heating down.

140 could not'be observed in the photographs taken. Equation (36) predicts that 61 must have a positive value for any (q/A) different from zero. It also predicts a minimum possible value of Y1 which increases with increasing ATsat. From a physical standpoint, this implies that the flow of vapor radially from the center of the disk is accompanied by a reduced thickness of the film as the distance from the center is increased. It also implies that there is a minimum film thickness which can exist on the disk for a given (q/A). This minimum thickness is necessary to remove the generated vapor. The minimum possible thickness increases with increasing ATsat, since the increasing rate of vapor generation results in a larger flow volume. The numerical values predicted for the minimum possible Yl, and the corresponding 61 are probably in error in this region'because the assumption that 61 << y1 is no longer valid. B. OTHER BOILING REGIMES 1. Minimum Heat Flux Boiling Most of the results presented in the minimum heat flux boiling region were obtained with the 1-inch diameter sphere. Insufficient data were obtained with the l/4l-inch diameter sphere and the disk to permit any conclusions to be reached from comparisons with existing correlations for (q/A)min. The results obtained with the 1-inch diameter sphere were compared with the behavior predicted by correlations.

141 Berenson3 developed an equation for (q/A)min as (P~-Pv1/2 1/4 1 /4 i/A 0.0 pf h f (go (44) min 0 09 Pvfhrg fS 1/ [P LgI- / Equation (44) is plotted on Figs. 44 and 51 for pressures of 1, 3, and 5 atmospheres. The experimental results for the 1-inch diameter sphere are also shown on Fig. 51. A range of (q/A)min at a particular (a/g) is shown by the two extreme points connected by a vertical line. A range of (q/A)min combined with an uncertainty in (a/g) is shown by two points connected by a diagonal line. Some (q/A)'s were obtained at ATsat differing from that at which (q/A)min was anticipated by -10~F to +350F. Since no data were obtained which were identified as (q/A)min for these conditions, the measured values, shown in Fig. 22, were taken as upper limits on (q/A)min. They are indicated'by a vertical line originating at the data points and terminating in an arrowhead. Equation (44) was developed for flat plates, but previous work done with the 1-inch sphere at 1 atmosphere pressure had shown reasonable agreement with the predicted values for (q/A)min at both standard and fractional gravity.19 Equation (44) does not predict the experimental results at higher pressures. An increase in (q/A)min of approximately 120% at 3 atmospheres and 200% at 5 atmospheres is predicted, but the experimental values increase by approximately 30% and 50%, respectively. The values of (q/A)min are predicted to follow a 1/4 power dependence on (a/g). The data shown in Fig. 51 appear to follow this predicted dependence. The power dependence n in (a/g)n is larger than 0.15 at a pressure of 3 atmospheres,

10 Pressure, Atmospheres 3 5 o a Experimental Data Eq. (44) Ref. 3 Eq. (45) Ref. 4 to. go Eq. (46) Ref. 47 1-inch Diameter SphereQ - 2,~a - - 0~~~~~~~~~~~~~~0 Oka~~~~~~~~~~ 10 -~~~~~~~~~~~~~~~~~~~~ 01 0.0] 0oO.~01 a/g 0.1 1.0 Fig. 51. (q/A),j, in saturated boiling.

143 and larger than 0.22 at a pressure of 5 atmospheres. Other correlations for (q/A)min were developed by Zu-ber4 and by Lienhard and Wong47. Zuberts equation, (q/A)min 2 4- 60 4 PCPv ] a (4) 5 n 60 3 vhfg(P~+PV)2J g is very similar to Berenson's except for the coefficient (60 — = 0.177). It also differs in that it evaluates properties at saturation conditions rather than at an average film temperature. Equation (45) is plotted on Fig. 51 for P = 1 atmosphere. It predicts values of (q/A)min which are approximately 200% higher than the experimental values. Lienhard and Wong47 predicted (q/A)min for a horizontal cylinder. Their expression accounts for the effect of surface tension in the transverse direction upon the Taylor instability of the interface. They obtained. m(/Al),in =0 5 r PvhfXg 17 0 B-Prv + /2g(pop) -./4 (q/A)min =0- 3 R K + (p +pv)Rj L o +R 4 I v I - I 1 (46) For cylinders larger than 1/4-inch diameter, this equation indicates that (q/A)min is inversely proportional to the test object radius within a few percent. It also indicates that (q/A)min is proportional to (a/g)-1/4 rather than (a/g)+1/4 as indicated by Berenson and Ziuber and experimentally verified.19 Equation (46) is shown on Fig. 51 for P = 1 atmosphere. A few (q/A)min values were obtained for the 1-inch diameter sphere with subcooled boiling at 3 and 5 atmospheres (see Fig. 21). They were approximately 65% higher than the (q/A),ij values obtained with saturated

144 boiling at 3 and 5 atmospheres. Berenson3 also developed an equation for (ATsat)min as (ATsat)min = 0.127 Pvfhfg (P P 2/ 1/2 j f ) (a) Equation (47) is plotted on Fig. 52 for P = 1 atmosphere. The experimental results for the 1-inch diameter sphere are also shown, A range of (ATsat)min at a particular value of (a/g) is shown by the two extreme points connected by a vertical line, An uncertainty in (a/g) is shown by two extreme points connected by a horizontal line. When an upper limit was obtained for (ATsat)min, it is indicated by a vertical line originating at the data point and terminating in an arrowhead. The values predicted for (ATsat)min were higher than the experimental values'by a factor of approximately two19 at (a/g) = 1, and the difference increases with decreasing (a/g). Berenson3 had determined (ATsat)min from the relationship (q/A)min (ATsat)min = (48) hmin where (q/A)min is given in Eq. (44) and h was given in Eq. (26). The relationship for h determined by Frederking and Clark31 for the 1-inch diameter sphere is _ Pvf(.-p f)g 1/3 h = 0.14 kvf'0 2.... a (49) This was substituted for Eq (26) n Eq (48) to obtavf This was substituted for Eqo (26):in Eqo (48) to obtain

Pressure, Atmospheres a 3 5 a Experimental Data Eq. (47) Ref. 3 Eq. (50) Ree. 31 400 1-inch Diameter Sphere P 5 atM Eq.(0 at,, q (50) 100 40 4, 0.001 Q.01 a/g 0.1 1.0 Fig. 52. (ATsat)min in saturated boiling.

146 (ATsat)min = 0465 Pvfhfg 1/2 g. o /8 1 /8 a-1/8. nkvf'vf LP +p)2 [jP-Pf (. ()0) This reduced the predicted value of (ATsat)min to 50% higher than the experimental values at P = 1 atmosphere and (a/g) = 1. Equation (50) is shown on Fig. 52 for P = 1, 3, and 5 atmospheres. A large increase is predicted in the value of (ATsat)min with increasing pressure. The experimental range of (ATsat)min at (a/g) = 1 shown in Fig. 52 for 1, 3, and 5 atmospheres does not appear to be affected by a change in pressure. The accuracy of the determination of (ATsat)min is +5~F, so a small effect of pressure would not be apparent. BerensonTs equation for (ATsat)min, Eq. (47), indicates a dependence on (a/g)-1/6 Equation (50), which utilizes Frederking and Clark's correlation for spheres inevaluating h, indicates a dependence on (a/g)-/8 As may be seen in Fig. 52, this difference is small. The experimental data do not show any effect of (a/g): All of the (ATsat)min, regardless of pressure or (a/g), fell in the range (ATsat)min = 500~+10F. A few (ATsat)min values were obtained for the 1-inch diameter sphere with subcooled boiling at 3 and 5 atmospheres (see Fig. 21). They fell in the 500~100F range found with saturated boiling. 2. Peak Heat Flux Boiling Figure 26 shows the peak heat flux is affected by both pressure and (a/g)o The correlations of Noyes20 and Zuber (discussion in Ref. 3) for saturated boiling most nearly predict the observed results. Noyest cor

147 relation is q/A = 0.144 h /2 LP rPv)2 i/ -gg p-~245 (a)l/4 (51) and Zuber's correlation is (q/A)max= C2hfg 1/2 [ggo(ppv)]i /4 (a5/4 (52) where 0.120 < C2 < 0.157 (53) For PrQ 1 and p ~>> Pv, these correlations are identical. They are shown in Fig. 53 for (a/g) = 1 and pressures from 1 to 5 atmospheres. Equation (51) is also shown for (a/g) < 1, and is included on Fig. 44. Values of (q/A) obtained with the 1-inch diameter sphere at 1, 3, and 5 atmospheres and with the 1/2-inch diameter sphere at 1 atmosphere are shown in Fig. 53. The agreement between the experimental and the predicted results over a range of pressures and (a/g) indicates that the correlation has wide applicability. Chang and Snyder21 also developed a correlation for (q/A)max identical to Eq. (52) with C2 = 0.145. They also developed an expression for the "critical temperature difference," which has been modified by Merte and Clark19 to apply to liquid nitrogen. In this form it appears as 03 (hfgPv)9/5a[ggoa(p-pv) ];/42/5 1/4 (ATsat)cr = C3x103 P,12k [Cp,(P~pv12/ 6,Apg

148 Sphere a/g __-__ Eq. (52) Diameter 1.0 0.6 0.33.17 Ref. 3 for a/g = 1 1 inch O 0 O 0 2 inch Eq. (51) Ref. 20 1/2 inch O Note: Data at P = 1 atm from Ref. 19 Saturated Liquid 10 _ N /~a/g = 1 _ / _ o.6 6 0.33 Pq/0 0.2 5 0.01 2x104 1 2 3 4 5 Pressure, atm Fig. 53. Comparison of experimental and predicted (q/A)max.

149 where 0.26 < C3 < 0.52 (55) and (ATsat)cr is the temperature difference at which (q/A)max is obtained. Equation (55) is shown in Fig. 44 for P = 1 atmosphere and a range of values of (a/g), and also for P = 3 and 5 atmospheres at (a/g) = 1. It may be noted that Eq. (55) predicts that (ATsat)cr will decrease as (a/g) decreases and also as the pressure is increased. A decrease of (ATsat)cr with decreasing (a/g) was observed on Fig. 26, but the predicted decrease of (ATsat)cr with increasing pressure is not seen on this figure. The effect of subcooling on peak heat flux is pronounced, as may be seen on Fig. 26. One correlation for predicting this effect is that proposed by Zuber,Tribus, and Westwater55 as quoted by Kreith2, which is given as i Xk~(Tsat-T~) 24 goPv a maxsc (/maxsat ( g /2 lthfgPV [ag(p Pv o] Lmitcel-rgo) _j'f gpv gL 1 ~ (56) where r 1 1/2 _- 1/4 T J ( r: 2 it (57) T -Lg(P-Pv L g(P —Pj The correlation of Noyes,20 Eq. (51), which predicted the experimental data quite accurately, was used for evaluating (q/A)maxsat. The ((q/A)max)sc was evaluated for 3 atmospheres at 15'F subcooling and for 5 atmospheres at 25~F subcooling at (a/g) = 1 and 0.17. The ratios of ((q/A)) x to ((q/A)maQsat were formed and are shown in Fig. 54. Also shown are the same

150 P, atm 3 5 Subcooling, OF 15 25 0 0 Experimental Data ____ Eq. (56) Ref. 55 (q/A)m from Eq. (51 sat Ref. 20 TIC 2.0 1-inch Diameter Sphere 2.0 1.5 -1050 1. 0.1 1.0 a/g Fig. 54. Effect of subcooling on (q/A)max.

151 ratios obtained from the experimental results with the 1-inch diameter sphere. The limited number of data points, particularly at (a/g) = 0.17, restricts the validity of the comparison of predicted and experimental values. With this restriction in mind, the prediction seems good at (a/g) = 1, but predicts too high a value at (a/g) = 0.17. The predicted value of (q/A)ma)sC(q/A)xmasat at (a/g) = 0.01 and 5 atmospheres with 25~F subcooling (not shown on Fig. 54) is 7.72. Although no data were obtained at this (a/g), the results shown on Fig. 25 for (a/g) < 0.002 do not indicate that a difference of this magnitude is probable. Until more experimental results at (a/g) < 1 are available, it appears Eq. (56) should be used with caution at (a/g) < 1. 3. Nucleate Boiling Saturated nucleate pool boiling has been investigated extensively, and many correlations have been developed which predict (q/A) as a function of ATsat (see, e.g., Fig. 5 of Ref. 44). The experimental results have exhibited wide variations of (q/A) with ATsat (see Fig. 35), so it is not surprising that the correlations exhibit similar variations. A survey was made to determine which correlations most accurately predicted the results obtained with the 1-inch diameter sphere with saturated nucleate boiling at 1 atmosphere and (a/g) = 1. The equation of Rohsenowll, given as I(a(q/A) ) = 2.97x105 / (Cpr) a1/2 (o) l/2(hfg)2 (go)l/2 (Pr58

152 and of Michenkol2, given as (6 l[g(P —Pv)] (go)l/2p (q/A) = 6.3x 101llO 1/2 (hfgPv) (go) (Pr) g(Pr-P 1 (x) (Cp )1o/3(p )7/3(T1/3(a/g)- (59)/3 most nearly predicted the experimental results. Rohsenow predicts (q/A) is proportional to (ATsat)3 which is virtually the same as that of Michenko, (ATsat)1l/3. The measured slope of the reference curve (as introduced in Chapter VI) in the nucleate boiling region is 3.4. The prediction of Rohsenow incorporates an empirical constant which must be reevaluated for each system. Variations in saturated nucleate boiling heat flux with variations in pressure have been predicted (see, e.g., Ref. 44). The variations predicted by Eq. (58) and (59) are shown on Fig. 55, evaluated for liquid nitrogen with ATsat = 10~F. Experimental results are shown in Fig. 55. The point at 1 atmosphere is taken from the reference curve, and the error limits represent a combination of ~20% maximum error in (q/A) and ~1~F maximum error in ATsat; the maximum total error is estimated to be +65%, -45%. Equation (58) predicts a decreasing effect of pressure on (q/A) as pressure increases; Eq. (59) predicts an increasing effect of pressure on (q/A) as pressure increases. The data appear to demonstrate an increasing effect of pressure on (q/A) as pressure increases. There is no apparent effect of variations in (a/g) on nucleate boiling. This has been observed by several authors (see, e.g., Refs. 16, 17, 18, 19,

105 a/g 1. 0.17 <0.002 O 0 Experimental Saturated Boiling Data O 1 U Experimental Subcooled Boiling Data (at 3 atm, sc = 15~F; at 5 atm, sc = 250F) Eq. (58) Ref. 11 Ea. (59) Ref. 12 1-inch Diameter Sphere AT 100F (Nucleate Boiling) P sat Fig.55.Effctfprssueadsbcolingonncleatebil04tfl O 1. 2. 3. 4. 5. Pressure, Atmospheres Fig. 55. Effect of pressure and subcooling on nucleate boiling heat flux.

154 and 56). It may be noted that Eq. (58) predicts a 1/2 power dependence on (a/g) and Eq. (59) predicts a -2/3 power, which indicates inadequacies in the models used in developing these correlations. Equation (58) is plotted on Fig. 44 to show the predicted effects of (a/g) and pressure. There are no apparent effects of subcooling on nucleate boiling as may be seen from Figs. 27 and 55. McAdamsl and Krieth2 have shown data plotted as (q/A) vs. ATsat over a wide range of variables and demonstrated that, for a given value of (q/A), nucleate boiling data fall within a range of ~35% of the nominal value of ATsat regardless of the degree of subcooling. Forster and Greif4 examined several proposed nucleate boiling mechanisms and concluded that the process of liqui.dvapor exchange taking place every time a bubble grows and then collapses on, or detaches.from, the heating surface can account for the heat flux in nucleate boiling. The effect of subcooling on the maximum bubble radius and the bubble lifetime largely cancel each other, accounting for the apparent insensitivity of heat flux to subcooling. When both of these factors were taken into account, Forster and Greifl4 showed that the data of Ellion50 for water which was subcooled from 350F to 1500F would not be expected to show more than 15% variation in heat flux. The correlations suggested for use with saturated nucleate boiling should be equally applicable to subcooled nucleate boiling. Figure 55 shows that subcooled nucleate boiling is not sensitive to variations in (a/g) within the range examined, again in contrast to the dependence predicted by the correlations.

155 4. Free Convection McAdamsl presents an equation for the correlation of data for single horizontal cylinders with heat transfer by natural convection. Kreith2 notes that this equation may also be applied to spheres. McAdams recommends application to cylinders only for 103 < Gr-Pr < 109. Kreith suggests use for 103 < Gr < 109 and Pr > 0.5 for cylinders, and suggests that for spheres, using the sphere radius as the characteristic length, Gr should be greater than 103. The equation is given by Kreith as Nu = 0.53 (Gr.Pr)l/4 (60) which may be rewritten as 3/A = P3 P gCp2/44 a 1/4 (61) q/A = 0.53 R(i (TS-T) / (6 Equation (61) is shown on Fig. 56 with the subcooled free convection data presented in Fig. 29. Agreement is good. Equation (60) was derived for laminar flow. The calculated values of Gr for these tests were'between 106 and 107. This normally indicates laminar flow, justifying application of Eq. (60). The correlation is relatively insensitive to variations in pressure in the region investigated because of the incompressibility of the liquid. The calculated value of (q/A) decreased by less than 4% when the pressure was increased from 3 to 5 atmospheres.

156 D P = 3 atm sc = 150F Nu = 0.53 (Gr.Pr)l/4 O P = 5 atm sc = 25~F P = 3 atm P = 5 atm 1-inch Diameter Sphere (a/g) = 1 C0 3 0 10 0 "!0,g 0 L5^~~(T-T OF Fig. 5. eat flux with free convection. 10-L I l I I I Il l l l Fig. 56. Heat flux with free convection.

CHAPTER VIII SUMMARY AND CONCLUSIONS The purpose of this study was to investigate the effect of variations in the gravitational field on the'boiling phenomena. In order to make the results as general as possible, several different physical configurations were investigated at various pressures and degrees of subcooling.. The results obtained, in addition to providing quantitative data, also permitted more complete comparisons between these data and various correlations which have been suggested for various boiling regimes. These comparisons in turn aid in determining the significance of various parameters in the effect they have on the boiling phenomena. The configurations investigated were a 1-inch diameter sphere, a 1/4inch diameter sphere, and a 3-inch diameter disk with the heating surface in a vertical, a horizontal heating up, and a horizontal heating down orientation. All of these configurations were investigated in the film-'boiling region, but only the l-inch diameter sphere results are presented in the other boiling regimes (minimum heat flux, transition, maximum heat flux, nucleate, and free-convection regions), Pressures used were 1, 3, and 5 atmospheres. Nominal subcooling levels of 15~F at 3 atmospheres and 25~F at 5 atmospheres were used as well as saturated conditions at all three pressures. The nonfilm boiling regions were not covered as comprehensively as the film boiling region, and in general only one or at most a few points were taken at any particular set of conditions. The reason 157

158 for this was the desire to examine a very wide range of new situations, rather than to cover a single combination in great depth. Over the range of accelerations, pressures, subcoolings, and configurations covered in this study, the following conclusions can be drawn: For a sphere for which the diameter is larger than the calculated value of Xd, 1. In the film-boiling region, (q/A) is proportional to (a/g)l/3 and decreases with increasing sphere diameter. 2. In the minimum heat flux region, (q/A)min is proportional to (a/g) /4, but (ATsat)min is not affected by variations in (a/g), pressure, or subcooling. 3. For values of ATsat between (ATsat)min and (ATsat)max, a sudden decrease in (a/g) causes a sudden decrease in (q/A) followed'by an increasing (q/A) with decreasing ATsat which has the appearance of transition boiling. The transient technique used here thus makes the relationship between (q/A) and ATsat a many-valued, rather than a single-valued, function in the transition boiling region with (a/g) less than 1. At (a/g) = 1, the (q/A) vs. ATsat relationship in the transition boiling regime was not affected'by pressure or su'bcooling. 4. The values of the peak heat flux and of (ATsat)max are proportional to (a/g)l/4. 5. Nucleate boiling is not affected by variations in (a/g), pressure, or subcooling; (qJA) is proportional to (ATsat)3'

159 For a disk or for a sphere for which the diameter is smaller than the calculated value of Xc, in the film-boiling region, 6. The heat flux is proportional to (a/g)2/9 7. The appearance of the vapor film on the disk changes significantly with a change in orientation. 8. For a flat plate or disk of sufficiently small dimensions (i.e., largest dimension 3 to 6 inches) there does not appear to be any effect of orientation on heat flux. 9. A change in the shape of the test surface (as from a sphere to a disk) may be accompanied by a change in (q/A) at a given ATsat.

APPENDIX A REDUCED DATA AND SAMPLE PHOTOGRAPHS 1. REDUCED HEAT TRANSFER DATA Column Headings. Run Number: for identification purposes Boiling Region: F, film; Min, (q/A)min; T, transition; Max, (q/A)max; N, nucleate; FC, free convection Pressure: in psia Subcooling: in "F a/g: measured sJA: in Btu/hr-ft2 T-T AT in OF Tsat Tsat in F Configuration: test -object shape, size, or orientation Pressurizing Medium: for pressures of approximately 14 psia, medium is understood to be atmospheric air; at higher pressures, compressed gas of indicated constitution was used

161 Run Boiling Pressure Subcooling a/g q/A T-Tsat Configuration Pressurizing Number Region Medium Run 27 27-B F 14.7 0 1 7,400 325 1/2-inch sphere 27-B F 14.7 0 1 6,900 298 1/2-inch sphere 27-B F 14.7 0 1 6,300 268 1/2-inch sphere 27-B F 14.7 0 1 4,480 180 1/2-inch sphere 27-B F 14.7 0 1 3,640 142 1/2-inch sphere 27-B F 14.7 0 1 3,250 111 1/2-inch sphere 27-B F 14.7 0 1 2,980 98 1/2-inch sphere 27-D F 14.7 0 1 2,210 60 1/2-inch sphere 27-D F 14.7 0 1 2,150 155 1/2-inch sphere 27-D Min 14.7 0 1 2,110 51 1/2-inch sphere 27-D T 14.7 0 1 2,350 45 1/2-inch sphere 27-D T 14.7 0 1 6,200 42 1/2-inch sphere 27-D T 14.7 0 1 10,300 41 1/2-inch sphere 27-D T 14.7 0 1 10,650 35 1/2-inch sphere 27-D T 14.7 0 1 35,000 30.5 1/2-inch sphere 27-D T 14.7 0 1 41,500 25 1/2-inch sphere 27-D Max 14.7 0 1 42,000 20.5 1/2-inch sphere 27-D N 14.7 0 1 32,000 15.5 1/2-inch sphere 27-D N 14.7 0 1 15,200 12.4 1/2-inch sphere 27-D N 14.7 0 1 7,580 10.4 1/2-inch sphere 27-D N 14.7 0 1 2,200 7.4 1/2-inch sphere 27-E F 14.7 0 1 7,980 310 1/2-inch sphere 27-E F 14.7 0 0 3,120 308 1/2-inch sphere 27-F F 14.7 0 1 6,100 258 1/2-inch sphere 27-F F 14.7 0 0 2,310 254 1/2-inch sphere 27-G F 14.7 0 1 4,740 200 1/2-inch sphere 27-G F 14.7 0 0 1,850 194 1/2-inch sphere 27-H F 14.7 0 1 3,520 135 1/2-inch sphere 27-H F 14.7 0 0 1,400 130 1/2-inch sphere Run 28 28-A F 14.7 0 1 2,040 61 1/2-inch sphere 28-A F 14.7 0 0 880 51.2 1/2-inch sphere 28-B F 14.7 0 1 2,050 60 1/2-inch sphere 28-B Min 14.7 0 1 2,000 50 1/2-inch sphere 28-B T 14.7 0 1 2,420 44 1/2-inch sphere 28-B T 14.7 0 0 1,450 43 1/2-inch sphere 28-B T 14.7 0 0 1,850 41 1/2-inch sphere 28-C F 14.7 0 1 1,800 49 1/2-inch sphere 28-C Min 14.7 0 1 1,770 42 1/2-inch sphere 28-C T 14.7 0 1 2,550 40 1/2-inch sphere 28-C T 14.7 0 0 920 39 1/2-inch sphere 28-C T 14.7 0 0 1,700 39 1/2-inch sphere 28-D T 14.7 0 1 2,100 43.5 1/2-inch sphere 28-D T 14.7 0 1 2,250 43 1/2-inch sphere 28-D T 14.7 0 1 2,650 42.5 1/2-inch sphere 28-D T 14.7 0 1 3,050 41.5 1/2-inch sphere 28-D T 14.7 0 1 4,700 40 1/2-inch sphere 28-D T 14.7 0 1 7,300 38 1/2-inch sphere 28-D T 14.7 0 1 14,600 32 1/2-inch sphere 28-D T 14.7 0 1 19,500 31 1/2-inch sphere 28-D T 14.7 0 1 25,500 27.5 1/2-inch sphere 28-D T 14.7 0 39,500 23.5 1/2-inch sphere 28-D Max 14.7 0 1 45,000 20.5 1/2-inch sphere 28-D N 14.7 0 1 43,800 18 1/2-inch sphere

162 Run Boiling Run Boiling Pressure Subcooling a/g q/A T-Tsat Configuration Pressurizing Number Region Medium 28-D N 14.7 0 1 43,000 15 1/2-inch sphere 28-D N 14.7 0 1 27,500 12.3 1/2-inch sphere 28-D N 14.7 0 1 17,700 10.7 1/2-inch sphere 28-D N 14.7 0 0 7,700 8.4 1/2-inch sphere 28-D N 14.7 0 0 3,300 7 1/2-inch sphere 28-D N 14.7 0 0 1,950 6.2 1/2-inch sphere 28-D N 14.7 0 0 1,580 4.8 1/2-inch sphere 28-E T 14.7 0 1 2,000 48 1/2-inch sphere 28-E T 14.7 0 1 2,600 47 1/2-inch sphere 28-E T 14.7 0 1 4,100 44 1/2-inch sphere 28-E T 14.7 0 1 5,100 42 1/2-inch sphere 28-E T 14.7 0 1 7,380 40.2 1/2-inch sphere 28-E T 14.7 0 1 12,000 37 1/2-inch sphere 28-E T 14.7 0 1 15,100 34.5 1/2-inch sphere 28-E T 14.7 0 0 14,800 32 1/2-inch sphere 28-E T 14.7 0 0 6,800 30.5 1/2-inch sphere 28-E T 14.7 0 0 10,600 27.5 1/2-inch sphere 28-E T 14.7 0 0 20,400 24.5 1/2-inch sphere 28-E T 14.7 0 0 15,200 22.5 1/2-inch sphere 28-E T 14.7 0 0 15,500 21 1/2-inch sphere 28-E T 14.7 0 0 25,400 18 1/2-inch sphere 28-F Min 14.7 0 1 1,850 49 1/2-inch sphere 28-F T 14.7 0 1 2,150 46 1/2-inch sphere 28-F T 14.7 o 1 5,850 42 1/2-inch sphere 28-F T 14.7 0 1 6,700 39 1/2-inch sphere 28-F T 14.7 0 1 10,,00 36 1/2-inch sphere 28-F T 14.7 0 1 16,700 33 1/2-inch sphere 28-F T 14.7 0 0 6,900 29 1/2-inch sphere 28-F T 14.7 0 0 13,400 26 1/2-inch sphere 28-F T 14.7 0 0 15,000 22.5 1/2-inch sphere 28-F T 14.7 0 c 18,800 20.2 1/2-inch sphere 28-F Max 14.7 0 0 21,000 17.2 1/2-inch sphere 28-F N 14.7 0 0 17,500 11.4 1/2-inch sphere 28-F N 14.7 0 0 11,500 9.3 1/2-inch sphere 28-F N 14.7 0 0 9,400 8.5 1/2-inch sphere Run 52 52-A Min 14.3 0 1 1,900 46 1-inch sphere 52-A T 14.3 0 1 2,140 45 1-inch sphere 52-A T 14.3 0 1 2,300 44 1-inch sphere 52-A T 14.3 0 0 1,005 43 1-inch sphere 52-B T 14.3 0 1 3,610 37 1-inch sphere 52-B T 14.3 0 1 3,800 36 1-inch sphere 52-B T 14.3 0 0 1,900 34 1-inch sphere 52-B T 14.3 0 0 1/,550 34 1-inch sphere 52-C T 14.3 0 1 9,150 33 1-inch sphere 52-C T 14.3 0 1 18,56o 30 1-inch sphere 52-C T 14.3 0 1 34,40o 27 1-inch sphere 52-C T 14.3 0 1 58,900 24 1-inch sphere 52-C T 14.3 0 0 10,500 22 1-inch sphere 52-C T 14.3 0 0 7,-200 21 1-inch sphere 52-C T 14.3 0 0 8,750,20 -inch sphere 52-C T 14.3 0 0 10,780 19 1-inch sphere 52-C T 14.3 o o 12,620 18 l-inch sphere 52-C T 14.3 o o 12,730 17 1-inch sphere 52-C Max 14.3 o o 14,470 16 1-inch sphere 52-C N 14.3 o o 14,o030 15 -inch sphere

163 Run Boiling Pressure Subcooling a/g q/A T-Tsat Configuration Pressurizing Number Region Medium 52-C N 14.3 0 0 14,180 14 1-inch sphere 52-C N 14.3 0 0 13,820 13 1-inch sphere 52-D T 14.3 0:0 18,800 32 1-inch sphere 52-D T 14.3 0 0 34,500 29 1-inch sphere 52-D T 14.3 0 0 37,100 23 1-inch sphere 52-D Max 14.3 0 0 41,900 20.5 1-inch sphere 52-D N 14.3 0 0 8,820 13.5 1-inch sphere 52-D N 14.3 0 0 6,810 10.5 1-inch sphere 52-E F 14.3 0 1 2,338 76 1-inch sphere 52-E F 14.3 0 0 442 74 1-inch sphere 52-E F 14.3 0 0 0 74 1-inch sphere 52-F F 14.3 0 1 3,035 115 1-inch sphere 52-F F 14.3 0 0 714 113 1-inch sphere 52-F F 14.3 0 0 494 113 1-inch sphere 52-G F 14.3 0 1 3,625 150 1-inch sphere 52-G F 14.3 0 0 986 148 1-inch sphere 52-G F 14.3 0 0 38o 148 1-inch sphere 52-H F 14.3 0 1 4,180 192 1-inch sphere 52-H F 14.3 0 0 900 190 1-inch sphere 52-H F 14.3 0 0 600 190 1-inch sphere 52-I F 14.3 0 1 4,405 213 1-inch sphere 52-I F 14.3 0 0 1,056 210 l-inch sphere 52-I F 14.3 0 0 808 210 l-inch sphere 52-J F 14.3 0 1 2,220 51 1-inch sphere 52-J F 14.3 0 1 1,800 50 1-inch sphere 52-J F 14.3 0 1 1,760 49 1-inch sphere 52-J F 14.3 0 0 178 48 1-inch sphere 52-J F 14.3 0 0 0 48 1-inch sphere 52-K T 14.3 0 1 2,014 43 1-inch sphere 52-K T 14.3 0 1 2,566 42 1-inch sphere 52-K T 14.3 0 1 3,034 41 1-inch sphere 52-K T 14.3 0 1 3,908 4o 1-inch sphere 52-K T 14.3 0 0 588 40 1-inch sphere 52-K T 14.3 0 0 859 39 l-inch sphere 52-L T 14.3 0 1 30,800 31 1-inch sphere 52-L T 14.3 0 1 34,260 28 1-inch sphere 52-L Max 14.3 0 1 41,300 24 1-inch sphere 52-L N 14.3 0 1 34,600 21 1-inch sphere 52-L N 14.3 0 1 29,000 18 1-inch sphere 52-L N 14.3 0 0 24,700 16 1-inch sphere 52-L N 14.3 0 0 20,360 15 1-inch sphere 52-L N 14.3 0 0 14,970 14 1-inch sphere 52-L N 14.3 0 0 10,970 13 1-inch sphere 52-L N 14.3 0 0 8,080 12 1-inch sphere 52-L N 14.3 0 0 5,910 11 1-inch sphere 52-L N 14.3 0 0 4,6oo00 10 1-inch sphere 52-L N 14.3 0 0 3,870 9 1-inch sphere 52-M F 14.3 0 1 2,064 65 1-inch sphere 52-M F 14.3 0 1 2,058 64 1-inch sphere 52-M F 14.3 0 1 2,052 63 1-inch sphere 52-M F 14.3 0 0 545 62 1-inch sphere 52-M F 14.3 0 0 425 62 1-inch sphere 52-N F 14.3 0 1 2,226 56 1-inch sphere 52-N F 14.3 0 1 1,774 55 1-inch sphere 52-N F 14.3 0 1 1,770 54 1-inch sphere 52-N F 14.3 0 0 755 53 1-inch sphere 52-N F 14.3 0 0 389 53 1-inch sphere

164 Run Boiling Pressurizing Pressure Subcooling a/g q/A T-Tsat Configuration Number Region Medium Run 55 55-A F 36.2 3-7 1 8,360 292 1-inch sphere Air 55-A F 36.2 3-7 1 7,310 246 1-inch sphere Air 55-A F 36.2 3-7 1 5,970 205 1-inch sphere Air 55-A F 36.2 3-7 1 4,850 152 1-inch sphere Air 55-A F 36.2 3-7 1 3,840 118 1-inch sphere Air 55-A F 36.2 3-7 1 3,170 84 1-inch sphere Air 55-A F 36.2 3-7 1 2,660 63 1-inch sphere Air 55-B F 37.3 8 1 6,600 192 l-inch sphere Air 55-C F 37.2 8 1 6,770 192 1-inch sphere Air 55-D F 37.2 6 1 3,860 104 l-inch sphere Air 55-D F 37.2 6 1 3,590 94 1-inch sphere Air 55-D F 37.2 6 1 3,340 84 1-inch sphere Air 55-E F 39.8 7 1 3,280 57 l-inch sphere Air 55-E Min 39.8 7 1 4,200 51 1-inch sphere Air 55-E T 39.8 1 1 12,340 40 l-inch sphere Air 55-E T 39.8 1 1 23,570 31 1-inch sphere Air 55-E T 39.8 1 1 53,130 25 1-inch sphere Air 55-E Max 39.8 1 1 76,020 21 1-inch sphere Air 55-E N 39.8 1 1 38,090 16 1-inch sphere Air 55-E N 39.8 1 1 10,560 12 1-inch sphere Air 55-E N 39.8 1 1 7,940 11.3 l-inch sphere Air 55-F F 37.5 10 1 9,060 285 l-inch sphere Air 55-F F 37.5 10 1 8,450 270 1-inch sphere Air Run 56 56-A F 65.3 6-11 1 12,070 315 1-inch sphere Air 56-A F 65.3 6-11 1 9,630 252 1-inch sphere Air 56-A F 65.3 6-11 1 8,340 206 l-inch sphere Air 56-A F 65.3 6-11 1 7,410 156 1-inch sphere Air 56-A F 65.3 6-11 1 5,140 108 1-inch sphere Air 56-A Min 65.3 6-11 1 3,980 65 1-inch sphere Air 56-A T 65.3 6-11 1 4,530 45 1-inch sphere Air 56-B F 66.4 11 1 14,650 312.5 l-inch sphere Air 56-C F 66.0 13 1 10,630 268 l-inch sphere Air 56-C F 66.0 13 1 9,830 256 1-inch sphere Air 56-D F 67.0 17 1 9,600 182 1-inch sphere Air 56-E F 66.6 13 1 6,040 96 1-inch sphere Air 56-E F 66.6 13 1 5,740 85 1-inch sphere Air 56-E F 66.6 13 1 5,340 74 l-inch sphere Air 56-F F 69.0 14 1 5,620 66 1-inch sphere Air 56-F F 69.0 14 1 4,890 56 1-inch sphere Air 56-F Min 69.0 14 1 4,690 48 l-inch sphere Air 56-F T 69.0 14 1 5,860 39 1-inch sphere Air 56-F T 69.0 14 1 10,960 38 l-inch sphere Air 56-F T 69.o 14 1 35,600 32 1-inch sphere Air 56-G Min 66.2 10 1 4,500 47 l-inch sphere Air 56-G T 66.2 10 1 8,350 42 1-inch sphere Air 56-G T 66.2 10 1 25,260 39 1-inch sphere Air 56-G T 66.2 10 1 53,110 28 l-inch sphere Air 56-G Max 66.2 10 1 90,930 22 1-inch sphere Air 56-G N 66.2 10 1 47,960 18 1-inch sphere Air 56-G N 66.2 10 1 16,460 14 1-inch sphere Air 56-G N 66.2 10 1 7,700 11 1-inch sphere Air 56-G N 66.2 10 1 1,320 7.2 1-inch sphere Air

165 Run Boiling Pressure Subcooling a/g q/A T-Tsat Configuration ressu g Number Region Medium 56-H T 69.6 25 1 7,580 44 l-inch sphere Helium 56-H T 69.6 25 1 19,010 37 1-inch sphere Helium 56-H T 69.6 25 1 61,340 32 l-inch sphere Helium 56-H Max 69.6 25 1 117,850 25 1-inch sphere Helium 56-H N 69.6 25 1 59,270 17 1-inch sphere Helium, 56-H N 69.6 25 1 20,710 14 l-inch sphere Helium 56-H N 69.6 25 1 5,030 8.4 1-inch sphere Helium 56-I F 69.2 24 1 15,400 310 1-inch sphere Helium Run 57 57-A F 44.5 18 1 11,200 305 1-inch sphere Helium 57-A F 44.5 18 1 10,750 292 l-inch sphere Helium 57-B-1 F 45.1 11 1 9,000 186 l-inch sphere Helium 57-B-1 F 45. 11 1 8,600 179 1-inch sphere Helium 57-B-2 F 44.5 17 1 8,900 200 1-inch sphere Helium 57-B-2 F 44.5 17 1 8,600 190 1-inch sphere Helium 57-B-2 F 44.5 17 1 8,150 179 1-inch sphere Helium 57-C F 44.4 16 1 6,o300 101 l-inch sphere Helium 57-C F 44.4 16 1 6,200 96 1-inch sphere Helium 57-C F 44.4 16 1 5,900 86 1-inch sphere Helium 57-D Min 44.9 16 1 4,270 53 1-inch sphere Helium 57-D T 44.9 16 1 13,200 41 1-inch sphere Helium 57-D T 44.9 16 1 38,100 34.5 l-inch sphere Helium 57-D Max 44.9 16 1 80,240 22.6 1-inch sphere Helium 57-D N 44.9 16 1 45,660 15.5 1-inch sphere Helium 57-D N 44.9 16 1 19,920 11 1-inch sphere Helium 57-E Max 45.3 15 1 88,900 20.8 1-inch sphere Helium 57-E N 45.3 15 1 29,580 11.1 1-inch sphere Helium 57-E N 45.3 15 1 8,300 7.2 1-inch sphere Helium 57-F F 73.3 28 1 14,800 290 l-inch sphere Helium 57-G F 73.3 27 1 10,800 175 1-inch sphere Helium 57-H F 73.3 26 1 7,010 94 l-inch sphere Helium 57-H F 73.3 26 1 6,250 82 1-inch sphere Helium 57-H F 73.3 26 1 5,960 71 1-inch sphere Helium 57-I T 74.9 27 1 7,400 39 1-inch sphere Helium 57-I T 74.9 27 1 18,130 37 1-inch sphere Helium 57-I T 74.9 27 1 64,450 34 1-inch sphere Helium 57-I Max 74.9 27 1 104,710 20.3 l-inch sphere Helium 57-I N 74.9 27 1 56,840 13.2 1-inch sphere Helium 57-I N 74.9. 27 1 22,130 8.1 1-inch sphere Helium 57-J FC 74.4 25 1 2,530 1.1 l-inch sphere Helium 57-K F 73.3 - 1.3 1 7,680 212 1-inch sphere Helium 57-L F 74.3 - 1.0 1 9,150 260 1-inch sphere Helium 57-M F 45.9 0 1 8,110 271 1-inch sphere Helium 57-N F 46.8 0 1 6,120 190 l-inch sphere Helium Run 58 58-A F 43.3 16 1 14,120 272 1/4-inch sphere Helium 58-B F 43.8 14 1 14,370 269 1/4-inch sphere Helium 58-C Min 42.5 13 1 9,960 69 1/4-inch sphere Helium 58-C T 42.5 13 1 25,420 45 1/4-inch sphere Helium 58-C T 42.5 13 1 47,120 35 1/4-inch sphere Helium 58-C Max 42.5 13 1 67,730 24 1/4-inch sphere Helium 58-C N 42.5 13 1 37,070 12 1/4-inch sphere Helium 58-C N 42.5 13 1 8,470 5 1/4-inch sphere Helium 58-D T 73-1 25 1 11,060 60 1/4-inch sphere Helium

166 Pressurizing Run Boiling Pressure Subcooling a/g q/A T-Tsat Configurationg Number Region Medium 58-D T 73.1 25 1 19,420 51 1/4-inch sphere Helium 58-D T 73.1 25 1 41,480 36 1/4-inch sphere Helium 58-D T 73.1 25 1 63,100 32 1/4-inch sphere Helium 58-D T 73.1 25 1 87,210 25 1/4-inch sphere Helium 58-D Max 73.1 25 1 134,990 20 1/4-inch sphere Helium 58-D N 73.1 25 1 83,620 18.4 1/4-inch sphere Helium 58-D N 73.1 25 1 55,750 11.7 1/4-inch sphere Helium 58-D N 73.1 25 1 34,270 9.5 1/4-inch sphere Helium 58-D N 73.1 25 1 19,890 7.6 1/4-inch sphere Helium 58-D N 73.1 25 1 15,180 6.4 1/4-inch sphere Helium 58-E F 74.6 23 1 18,930 311 1/4-inch sphere Helium 58-E F 74.6 23 1 17,870 282 1/4-inch sphere Helium 58-E F 74.6 23 1 17,320 253 1/4-inch sphere Helium 58-E F 74.6 23 1 16,150 210 1/4-inch sphere Helium 58-E F 74.6 23 1 14,000 171 1/4-inch sphere Helium 58-E F 74.6 23 1 13,050 135 1/4-inch sphere Helium 58-E F 74.6 23 1 11,570 100 1/4-inch sphere Helium 58-E Min 74.6 23 1 11,400 72 1/4-inch sphere Helium 58-E T 74.6 23 1 13,570 44 1/4-inch sphere Helium Run 59 59-A F 44.0 14 1 9,400 231 1-inch sphere Helium 59-A F 44.0 14 0 3,600 229 l-inch sphere Helium 59-A F 44.0 14 0 1,885 228 1-inch sphere Helium 59-B F 44.0 15 1 7,210 166 1-inch sphere Helium 59-B F 44.0 15 0 3,800 162 1-inch sphere Helium 59-B F 44.0 15 0 1,747 161 1-inch sphere Helium 59-C F 45.0 14 1 6,190 105 l-inch sphere Helium 59-C F 45.0 14 0 3,060 101 l-inch sphere Helium 59-C F 45.0 14 0 1,905 100 1-inch sphere Helium 59-D F 44.0 15 1 4,960 66 1-inch sphere Helium 59-D F 44.0 15 0 3,260 62.6 1-inch sphere Helium 59-D F 44.0 15 0 1,352 61.5 1-inch sphere Helium Run 60 60-A T 44.1 14 1 5,030 44 1-inch sphere Helium 60-A T 44.1 14 1 6,800 40 1-inch sphere Helium 60-A T 44.1 14 0 8,790 35 1-inch sphere Helium 60-A T 44.1 14 0 5,310 34.2 1-inch sphere Helium 60-A T 44.1 14 0 2,590 33.8 1-inch sphere Helium 60-A T 44.1 14 0 6,130 33 1-inch sphere Helium 60-B No Data 60-C T 44.2 16 1 42,230 30.5 1-inch sphere Helium 60-C T 44.2 16 1 95,750 25.4 1-inch sphere Helium 60-C Max 44.2 16 0 104,270 22.4 1-inch sphere Helium 60-C N 44.2 16 0 78,670 19.7 1-inch sphere Helium 60-C N 44.2 16 0 38,750 16.2 1-inch sphere Helium 60-C N 44.2 16 0 16,470 12.5 1-inch sphere Helium 60-C N 44.2 16 0 5,010 8.8 1-inch sphere Helium 60-D T 44.2 15 1 16,060 41 1-inch sphere Helium 60-D T 44.2 15 0 13,140 33 1-inch sphere Helium 60-D T 44.2 15 0 8,100 32.2 1-inch sphere Helium 60-D T 44.2 15 0 20,580 28 1-inch sphere Helium 60-D T 44.2 15 0 22,290 23.4 1-inch sphere Helium 60-E T 44.0 15 1 4,920 47 1-inch sphere Helium 60-E T 44.0 15 1 7o80 43 1-inch sphere Helium

167 Run Boiling Pressure Subcooling a/g q/A T-Tsat Configuration Pressurizing Number Region Medium 60-E T 44.0 15 0 7,810 42.7 1-inch sphere Helium 60-E T 44.0 15 0 6,o80 39.3 1-inch sphere Helium 60-F N 44.5 17 1 2,750 7 l-inch sphere Helium 60-F N 44.5 17 1 2,520 6.1 1-inch sphere Helium 60-F N 44.5 17 0 2,420 5.7 1-inch sphere Heliut 60-F N 44.5 17 0 1,830 5 1-inch sphere Helium 60-F N 44.5 17 0 1,270 4.7 1-inch sphere Helium 60-G T 44.5 17 1 38,580 40 1-inch sphere Helium 60-G T 44.5 17 1 72,240 30.6 1-inch sphere Helium 60-G T 44.5 17 0 80,890 26.3 l-inch sphere Helium 60-G T 44.5 17 0 63,720 23.8 1-inch sphere Helium 60-G T 44.5 17 0 27,470 22.8 l-inch sphere Helium 60-G T 44.5 17 0 13,990 19.9 1-inch sphere Helium 60-G T 44.5 17 0 20,000 18 l-inch sphere Helium 60-G Max 44.5 17 0 23,710 16 1-inch sphere Helium 60-G N 44.5 17 0 20,550 14.1 1-inch sphere Helium 60-G N 44.5 17 0 10,210 10.9 1-inch sphere Helium Run 61 61-A F 73-7 27 1 11,800 215 1-inch sphere Helium 61-A F 73.7 27 0 2,990 209 l-inch sphere Helium 61-B F 73.0 25 1 9,790 158 1-inch sphere Helium 61-B F 73.0 25 0 2,930 153 1-inch sphere Helium 61-C F 72.4 29 1 6,770 89 1-inch sphere Helium 61-C F 72.4 29 0 1,986 84 1-inch sphere Helium 61-D F 74.0 50 1 6,o080 52 1-inch sphere Helium 61-D F 74.0 30 0 3,440 46 1-inch sphere Helium 61-E T 74.0 33 1 5,111 42.6 1-inch sphere Helium 61-E T 74.0 33 1 23,633 38.6 1-inch sphere Helium 61-E T 74.0 33 1 49,488 37.3 l-inch sphere Helium 61-E T 74.0 33 1 62,739 35.3 1-inch sphere Helium 61-E T 74.0 33 1 58,344 29.6 1-inch sphere Helium 61-E N 74.0 33 0 51,575 29 1-inch sphere Helium 61-E N 74.0 33 0 31,139 20.8 1-inch sphere Helium 61-E N 74.0 33 0 26,211 13.7 1-inch sphere Helium 61-E N 74.0 33 0 16,187 10.6 1-inch sphere Helium 61-F T 74.4 27 1 8,o59 44.8 1-inch sphere Helium 61-F T 74.4 27 1 11,733 41.9 1-inch sphere Helium 61-F T 74.4 27 0 21,573 36.3 1-inch sphere Helium 61-F T 74.4 27 0 28,540 27.9 1-inch sphere Helium 61-F T 74.4 27 0 42,570 21.4 1-inch sphere Helium 61-G T 74.0 28 1 8,450 40.2 1-inch sphere Helium 61-G T 74.0 28 1 14,245 37.2 1-inch sphere Helium 61-G T 74.0 28 1 51,580 32.5 1-inch sphere Helium 61-G N 74.0 28 0 90,473 23.2 1-inch sphere Helium 61-G N 74.0 28 0 59,886 18.9 1-inch sphere Helium 61-G N 74.0 28 0 16,558 9.2 1-inch sphere Helium 61-G N 74.0 28 0 7,054 7.0 1-inch sphere Helium 61-H T 75.0 30 1 5,771 43-.3 1-inch sphere Helium 61-H T 75.0 30 1 30,231 33.5 1-inch sphere Helium 61-H T 75.0 30 1 71,408 28.9 1-inch sphere Helium 61-H N 75.0 30 0 98,431 19.7 1-inch sphere Helium 61-H N 75.0 30 0 60,958 17.1 1-inch sphere Helium 61-H N 75.0 30 0 17,9355 9.0 1 —inch sphere Helium 61-H N 75.0 30 0 3,064I 5.9 1-inch sphere Helium

168 Run Boiling Pressurizing Number Region Pressure Subcooling a/g q/A T-Tsat ConfPiguration Pressurizing Number Region Medium Run 62 62-A F 74.2 28 0 5,810 185 1/4-inch sphere Helium 62-B F 75.6 28 1 9,010 62 1/4-inch sphere Helium 62-B F 75.6 28 1 8,070 45 1/4-inch sphere Helium 62-B Min 75.6 28 0 7,940 33 1/4-inch sphere Helium 62-B T 75.6 28 1 9,510 30 1/4-inch sphere Helium 62-B T 75.6 28 0 16,360 26 1/4-inch sphere Helium 62-B T 75.6 28 1 34,870 23 1/4-inch sphere Helium 62-B T 75.6 28 1 42,150 21 1/4-inch sphere Helium 62-B T 75.6 28 1 44,300 16.8 1/4-inch sphere Helium 62-B T 75.6 28 0 54,380 13.8 1/4-inch sphere Helium 62-B Max 75.6 28 0 63,050 10.8 1/4-inch sphere Helium 62-B N 75.6 28 0 61,540 7.6 1/4-inch sphere Helium 62-C Min 74.8 28 1 7,160 61 1/4-inch sphere Helium 62-C T 74.8 28 1 7,700 45 1/4-inch sphere Helium 62-C T 74.8 28 0 8,380 34 1/4-inch sphere Helium 62-C T 74.8 28 0 14,370 26 1/4-inch sphere Helium 62-C T 74.8 28 0 27,890 19 1/4-inch sphere Helium 62-C T 74.8 28 0 31,360 14 1/4-inch sphere Helium 62-C T 74.8 28 0 35,860 8.3 1/4-inch sphere Helium 62-C T 74.8 28 0 36,080 5.6 1/4-inch sphere Helium 62-D F 75.2 29 1 9,440 157 1/4-inch sphere Helium 62-D F 75.2 29 1 8,390 147 1/4-inch sphere Helium 62-D F 75.2 29 0 7,630 136 1/4-inch sphere Helium 62-D F 75.2 29 0 6,470 126 1/4-inch sphere Helium 62-E F 73.2 28 1 7,550 84 1/4-inch sphere Helium 62-E F 73.2 28 0 7,130 57 1/4-inch sphere Helium Run 63 63-A F 14.6 - 2 1 6,720 242 1/4-inch sphere 63-A F 14.6 - 2 0.17 4,360 229 1/4-inch sphere 63-B F 14.6 0 1 4,360 184 1/4-inch sphere 63-B F 14.6 0 0.17 3,370 168 1/4-inch sphere 63-C F 44.0 16 1 7,400 221 1/4-inch sphere Helium 63-C F 44.0 16 0.17 3,550 202 1/4-inch sphere Helium 63-D F 73.9 26 1 12,000 203 1/4-inch sphere Helium 63-D F 73.9 26 0.17 7,050 178 1/4-inch sphere Helium 63-E F 76.9 0 1 8,800 177 1/4-inch sphere Helium 63-F F 77.1 - 1 1 9,400 204 1/4-inch sphere Helium 63-F F 77.1 - 1 0.17 5,4oo00 175 1/4-inch sphere Helium 63-G F 46.0 0 1 8,850 218 1/4-inch sphere Helium 63-G F 46.o 0 0.17 6,000 200 1/4-inch sphere Helium 63-H F 44.7 14 1 9,560 166 1/4-inch sphere Helium 63-H F 44.7 14 1 8,370 156 1/4-inch sphere Helium 63-H F 44.7 14 0.17 5,770 136 1/4-inch sphere Helium 63-I F 74.7 26 1 10,550 150 1/4-inch sphere Helium 63-I F 74.7 26 0.17 6,o60 120 1/4-inch sphere Helium 63-J F 14.0 0 1 5,140 180 1/4-inch sphere 63-J F 14.0 0 0.17 3,400 165 1/4-inch sphere 63-K F 14.0 0 1 3,670 110 1/4-inch sphere 63-K F 14.0 0 0.17 2,360 98 1/4-inch sphere 63-L F 45.5 18 1 7,300 100 1/4-inch sphere Helium 63-L F 45.5 18 0.17 5,770 70 1/4-inch sphere Helium 63-M F 73.8 27 1 9,070 85 1/4-inch sphere Helium 63-M F 73.8 27 0.17 7,800 50 1/4-inch sphere Helium 63-N F 14.0 0 1 3,120 57 1/4-inch sphere Helium

169 Run Boiling Pressurizing Run Boiling Pressure Subcooling a/g q/A T-Tsat Configuration Medium Number Region 63-N F 14.0 0 0.17 2,050 49 1/4-inch sphere Helium 63-0 F 44.3 17 1 7,470 72 1/4-inch sphere Helium 63-0 Min 44.3 17 1 6,570 56 1/4-inch sphere Helium 63-0 T 44.3 17 1 6,940 42 1/4-inch sphere Heliun 63-0 T 44.3 17 1 9,700 40 1/4-inch sphere Helium 63-0 T 44.3 17 0.17 19,770 37 1/4-inch sphere Helium 63-0 T 44.3 17 0.17 35,020 32 1/4-inch sphere Helium 63-0 Max 44.3 17 0.17 57,060 21 1/4-inch sphere Helium 63-0 N 44.3 17 0.17 48,560 14.2 1/4-inch sphere Helium 63-0 N 44.3 17 0.17 35,530 10.9 1/4-inch sphere Helium 63-o N 44.3 17 0.17 21,010 8.2 1/4-inch sphere Helium 63-0 N 44.3 17 0.17 9,570 5.4 1/4-inch sphere Helium 63-P T 76.0 29 1 9,330 57 1/4-inch sphere Helium 63-P T 76.0 29 1 10,190 50 1/4-inch sphere Helium 63-P T 76.0 29 0.17 13,700 42 1/4-inch sphere Helium 63-P T 76.0 29 0.17 41,640 33 1/4-inch sphere Helium 63-P Max 76.0 29 0.17 79,230 18.4 1/4-inch sphere Helium 63-P N 76.0 29 0.17 55,370 10.2 1/4-inch sphere Helium 63-P N 76.0 29 0.17 26,240 5.3 1/4-inch sphere Helium 63-Q F 74.8 28 0.17 9,590 60 1/4-inch sphere Helium 63-Q Min 74.8 28 0.17 9,580 42 1/4-inch sphere Helium 63-Q T 74.8 28 0.17 30.560 34 1/4-inch sphere Helium 63-Q T 74.8 28 0.17 49,480 31 1/4-inch sphere Helium 63-Q Max 74.8 28 0.17 73,550 24 1/4-inch sphere Helium 63-Q N 74.8 28 0.17 72,270 16 1/4-inch sphere Helium 63-Q N 74.8 28 0.17 58,680 12 1/4-inch sphere Helium 63-Q N 74.8 28 0.17 22,050 7 1/4-inch sphere Helium 63-R N 14.0 - 1 1 19,600 10.9 1/4-inch sphere 63-R N 14.0 - 1 1 14,050 9.9 1/4-inch sphere 63-R N 14.0 - 1 1 10,120 9.2 1/4-inch sphere 63-R N 14.0 - 1 1 6,940 8.8 1/4-inch sphere 63-R N 14.0 - 1 1 4,050 7.8 1/4-inch sphere 63-R N 14.0 - 1 0.17 3,450 7.2 1/4-inch sphere 63-R N 14.0 - 1 0.17 2,380 6.0 1/4-inch sphere 63-R N 14.0 - 1 0.17 1,620 4.6 1/4-inch sphere 63-R N 14.0 - 1 0.17 1,080 4.o /1/-inch sphere 63-s N 44.5 16 1 49,240 10.6 1/4-inch sphere Helium 63-s N 44.5 16 1 23,920 8.0 1/4-inch sphere Helium 63-s N 44.5 16 1 13,830 6.1 1/4-inch sphere Helium 63-s N 44.5 16 1 8,200 50 1/4-inch sphere Helium 63-T FC 75.8 28 1 2,610 - 9 1/4-inch sphere Helium 63-T FC 75.8 28 0.17 957 -15 1/4-inch sphere Helium 63-U FC 44.4 16 1 659 - 9 1/4-inch sphere Helium 63-U FC 44.4 16 0.17 404 -12 1/4-inch sphere Helium 63-v N 75.8 27 1 107,260 13.3 1/4-inch sphere Helium 63-V N 75.8 27 1 59,100 9.3 1/4-inch sphere Helium 63-V N 75.8 27 1 27,980 6.3 1/4-inch sphere Helium Run 64 64-A F 74.4 23 1 11,600 202 1-inch sphere Helium 64-A F 74.4 23 1 10,350 198 1-inch sphere Helium 64-A F 74.4 23 0.17 6,ooo 193 1-inch sphere Helium 64-C F 74.8 26 0.17 8,530 295 1-inch sphere Helium 64-D F 45.1 15 1 12,450 316 1-inch sphere Helium 64-D F 45.1 15 1 10,94~0 312 1-inch sphere Helium

170 Run Boiling Run Boiling Pressure Subcooling a/g q/A TTt Configuration Pressurizing Number Region Medium 64-D F 45.1 15 0.17 5,750 306 1-inch sphere Helium 64-E F 45.1 12 0.17 5,100 83 1-inch sphere Helium 64-E F 45.1 12 0.17 3,450 78 1-inch sphere Helium 64-F F 74.2 22 1 5,850 72 1-inch sphere Helium, 64-F F 74.2 22 0.17 4,340 67 1-inch sphere Helium 64-G Min 44.2 15 1 4,420 44 1-inch sphere Helium 64-G T 44.2 15 1 6,690 41 1-inch sphere Helium 64-G T 44.2 15 0.17 21,120 34 1-inch sphere Helium 64-G T 44.2 15 0.17 30,400 29 1-inch sphere Helium 64-G Max 44.2 -15 0.17 60,880 22 1-inch sphere Helium 64-G N 44.2 15 0.17 33,460 14.7 1-inch sphere Helium 64-G N 44.2 15 0.17 15,450 11.6 1-inch sphere Helium 64-H Min 75.2 23 1 5,350 46 1-inch sphere Helium 64-H T 75.2 23 0.17 3,800 41 1-inch sphere Helium 64-H T 73.8 22 1 9,910 38.7 l-inch sphere Helium 64-H T 73.8 22 1 14,560 38 l-inch sphere Helium 64-I T 73.8 22 0.17 25,990 33.8 1-inch sphere Helium 64-I T 73.8 22 0.17 73,200 22.3 1-inch sphere Helium 64-I T 73.8 22 0.17 87,890 19.9 1-inch sphere Helium 64-I Max 73.8 22 0.17 97,250 18.9 1-inch sphere Helium 64-I N 73.8 22 0.17 60,220 15.5 1-inch sphere Helium 64-I N 73.8 22 0.17 14,850 9.5 1-inch sphere Helium 64-J T 44.2 12 1 36,900 33 1-inch sphere Helium 64-J Max 44.2 12 0.17 94,130 22.4 1-inch sphere Helium 64-J N 44.2 12 0.17 53,220 18 1-inch sphere Helium 64-J N 44.2 12 0.17 12,050 10.2 1-inch sphere Helium 64-K Max 73.7 22 1 114,290 19 1-inch sphere Helium 64-K N 73.7 22 1 28,560 10.8 1-inch sphere Helium 64-K N 73.7 22 1 6,890 6 1-inch sphere Helium 64-K N 73.7 22 0.17 4,430 4 1-inch sphere Helium 64-K N 73.7 22 0.17 1,710 2.3 1-inch sphere Helium 64-L F 79.2 1 1 7,370 199 1-inch sphere Helium 64-L F 79.2 1 0.17 3,940 194 1-inch sphere Helium 64-M F 45.0 1 1 6,350 211 1-inch sphere Helium 64-M F 45.0 1 0.17 3,130 205 1-inch sphere Helium 64-N F 72.8 1 1 3,200 69 1-inch sphere Helium 64-N F 72.8 1 0.17 1,700 67 1-inch sphere Helium 64-N F 72.8 1 0.17 2,040 66 1-inch sphere Helium 64-o F 44.7 0 1 2,820 80 1-inch sphere Helium 64-0 F 44.7 0 0.17 2,050 78 1-inch sphere Helium Run 65 65-A F 14.3 0 1 12,800 301 Vertical disk 65-A F 14.3 0 1 10,710 231 Vertical disk 65-A F 14.3 0 1 8,150 161 Vertical disk 65-A F 14.3 0 1 5,780 101 Vertical disk 65-A F 14.3 0 1 4,110 61 Vertical disk 65-B F 44.3 0-12 1 19,930 281 Vertical disk Helium 65-B F 44.3 0-12 1 16,300 201 Vertical disk Helium 65-B F 44.3 0-12 1 12,920 141 Vertical disk Helium 65-B F 44.3 0-12 1 9,440 101 Vertical disk Helium 65-B F 44.3 0-12 1 6,86o 61 Vertical disk Helium 65-C F 74.3 2-18 1 21,990 260 Vertical disk Helium 65-C F 74.3 2-18 1 18,560 190 Vertical disk Helium 65-C F 74.3 2-18 1 13,050 130 Vertical disk Helium 65-C F 74.3 2-18 1 9,080 90 Vertical disk Helium 65-C F 74.3 2-18 1 8,o80 70 Vertical disk Helium

171 Run Boiling Pressurizing Pressure Subcooling a/g q/A T-Tsat Configuration Number Region Medium 65-C F 74.3 2-18 1 7,540 60 Vertical disk Helium 65-D Min 14.3 0 1 5,190 49 Vertical disk 65-D T 14.3 0 1 15,300 46 Vertical disk 65-D T 14.3 0 1 54,020 40 Vertical disk 65-D Max 14.3 0 1 71,560 31 Vertical disk 65-D N 14.3 0 1 60,620 22 Vertical disk 65-D N 14.3 0 1 20,650 13 Vertical disk 65-D N 14.3 0 1 10,070 10 Vertical disk 65-D N 14.3 0 1 2,530 3.7 Vertical disk Run 66 66-A F 14.0 1.5 1 12,250 309 Vertical disk 66-A F 14.0 1.5 0.16 7,500 305 Vertical disk 66-B F 14.0 - 1.5 1 10,420 229 Vertical disk 66-B F 14.0 - 1.5 0.16 7,200 225 Vertical disk 66-C F 14.0 1 7,330 117 Verticat disk 66-C F 14.0 1 0.16 5,570 114 Vertical disk 66-D F 42.9 11 1 19,270 292 Vertical disk Helium 66-D F 42.9 11 0.16 13,300 286 Vertical disk Helium 66-E F 44.3 6 1 16,760 211 Vertical disk Helium 66-E F 44.3 6 0.16 11,040 205 Vertical disk Helium 66-F F 70.9 19 1 29,000 201 Vertical disk Helium 66-F F 70.9 19 0.16 20,960 193 Vertical disk Helium 66-G F 73.4 20 1 22,800 279 Vertical disk Helium 66-G F 73.4 20 0.16 16,000 274 Vertical disk Helium 66-H F 74.4 11 1 13,040 91 Vertical disk Helium 66-H F 74.4 11 0.16 8,610 88 Vertical disk Helium 66-H F 74.4 11 0.16 6,210 86 Vertical disk Helium 66-i F 45.7 3 1 9,480 88 Vertical disk Helium 66-I F 45.7 3 0.16 7,150 84 Vertical disk Helium Run 67 67-A F 14.3 - 1 1 7,130 119 Vertical disk 67-A F 14.3 - 1 0 3,600 117 Vertical disk 67-B F 14.3 0 1 12,500 307 Vertical disk 67-B F 14.3 0 0 6,360 303 Vertical disk 67-C F 14.3 0 1 10,630 228 Vertical disk 67-C F 14.3 0 0 5,900 224 Vertical disk 67-D F 75.3 20 1 24,200 279 Vertical disk Helium 67-D F 75.3 20 0 12,150 273 Vertical disk Helium 67-E F 75.3 9 1 11,930 89 Vertical disk Helium 67-E F 75.3 9 0 5,520 85 Vertical disk Helium 67-F F 79.3 17 1 20,550 200 Vertical disk Helium 67-F F 79.3 17 0 8,800 194 Vertical disk Helium 67-G F 42.8 9 1 17,100 211 Vertical disk Helium 67-G F 42.8 9 0 8,820 206 Vertical disk Helium 67-H F 44.3 1 1 8,710 99 Vertical disk Helium 67-H F 44.3 1 0 5,460 96 Vertical disk Helium 67-I F 46.3 12 1 19,500 290 Vertical disk Helium 67-I F 46.3 12 0 8,900 285 Vertical disk Helium Run 68 68-A F 50.8 2 1 15,160 287 Vertical disk Nitrogen 68-A F 50.8 2 0 8,325 283 Vertical disk Nitrogen 68-B F 47.8 0 1 14,420 199 Vertical disk Nitrogen 68-B F 47.8 0 0 6,340 196 Vertical disk Nitrogen

172 Run Boiling Run Boiling Pressure Subcooling a/g q/A T-Tsat ConfigPressurizing Number Region Medium 68-C F 45.5 1 1 8,670 99 Vertical disk Nitrogen 68-C F 45.5 1 0 5,990 96 Vertical disk Nitrogen 68-D F 77.3 2 1 11,350 234 Vertical disk Nitrogen 68-D F 77.3 2 0 5,580 231 Vertical disk Nitrogen 68-E F 76.3 1 1 16,000 183 Vertical disk Nitrogeh 68-E F 76.3 1 0 11,160 179 Vertical disk Nitrogen 68-E F 76.3 1 0 10,180 177 Vertical disk Nitrogen 68-F F 74.5 0 1 12,610 114 Vertical disk Nitrogen 68-F F 74.5 0 0 9,150 110 Vertical disk Nitrogen 68-G F 44.6 - 5 1 13,710 207 Vertical disk Nitrogen 68-G F 44.6 - 5 0.16 11,080 203 Vertical disk Nitrogen 68-H F 46.1 - 3 1 14,960 288 Vertical disk Nitrogen 68-H F 46.1 - 0.16 10,590 284 Vertical disk Nitrogen 68-I F 45.4 0 1 47,800 94 Vertical disk Nitrogen 68-I F 45.4 0 0.16 41,200 80 Vertical disk Nitrogen 68-J F 77.1 0 1 16,800 275 Vertical disk Nitrogen 68-J F 77.1 0 0.16 12,230 270 Vertical disk Nitrogen 68-K F 73.1 - 6 1 14,150 196 Vertical disk Nitrogen 68-K F 73.1 - 6 0.16 12,170 191 Vertical disk Nitrogen 68-L F 78.3 - 4 1 11,080 110 Vertical disk Nitrogen 68-L F 78.3 - 4 0.16 8,590 107 Vertical disk Nitrogen 68-M F 74.3 0 1 18,420 260 Vertical disk Nitrogen 68-M F 74.3 - 2 1 15,650 190 Vertical disk Nitrogen 68-M F 74.3 - 1.9 1 12,880 140 Vertical disk Nitrogen 68-M F 74.3 - 1.7 1 10,080 90 Vertical disk Nitrogen 68-M F 74.3 - 1.3 1 9,400 70 Vertical disk Nitrogen 68-M F 74.3 - 1.3 1 7,810 50 Vertical disk Nitrogen 68-N F 43.7 1.6 1 16,320 281 Vertical disk Nitrogen 68-N F 43.7 - 1.9 1 13,200 201 Vertical disk Nitrogen 68-N F 43.7 - 0.7 1 10,410 141 Vertical disk Nitrogen 68-N F 43.7 0.1 1 8,500 101 Vertical disk Nitrogen 68-N F 43.7 0.5 1 7,567 65 Vertical disk Nitrogen 68-N F 43.7 o.8 1 6,865 41 Vertical disk Nitrogen Run 69 69-A F 14.4 - 6- -13 1 9,570 308 Disk heating up 69-A F 14.4 - 6- -13 1 10,990 244 Disk heating up 69-A F 14.4 - 6- -13 1 8,900 202 Disk heating up 69-A F 14.4 - 6 -13 1 7,010 155 Disk heating up 69-A F 14.4 - 6- -13 1 6,540 117 Disk heating up 69-A F 14.4 - 6 -13 1 6,250 95 Disk heating up 69-A Min 14.4 - 6- -13 1 5,340 75 Disk heating up 69-A T 14.4 - 6- -13 1 5,920 60 Disk heating up 69-A T 14.4 - 6- -13 1 8,650 56 Disk heating up 69-A T 14.4 - 6- -13 1 18,610 49 Disk heating up 69-B F 69.6-80.8 1-4 1 16,510 271 Disk heating up Nitrogen 69-B F 69.6-80.8 1-4 1 13,980 202 Disk heating up Nitrogen 69-B F 69.6-80.8 1-4 1 12,250 160 Disk heating up Nitrogen 69-B F 69.6-80.8 1-4 1 11,550 119 Disk heating up Nitrogen 69-B F 69.6-80.8 1-4 1 10,500 90 Disk heating up Nitrogen 69-B F 69.6-80.8 1-4 1 9, 840 69 Disk heating up Nitrogen 69-B Min 69.6-80.8 1-4 1 8,810 58 Disk heating up Nitrogen 69-B T 69.6-80.8 1-4 1 15,000 48 Disk heating up Nitrogen 69-C F 76.6 - 5 1 16,770 275 Disk heating up Nitrogen 69-C F 76.6 - 5 0.16 13,500 270 Disk heating up Nitrogen 69-D F 72.9 - 4 1 13,920 196 Disk heating up Nitrogen 69-D F 72.9 - 4 0.16 11,100 192 Disk heating up Nitrogen

173 Run Boiling Pressurizing Pressure Subcooling a/g q/A Tsat Configuration Pressurizing Number Region Medium 69-E F 80.3 - 2 1 11,410 110 Disk heating up Nitrogen 69-E F 80.3 - 2 0.16 8,970 106 Disk heating up Nitrogen 69-F F 73.1-78.3 0-18 1 31,170 265 Disk heating up Helium 69-F F 73.1-78.3 0-18 1 17,300 207 Disk heating up Helium 69-F F 73.1-78.3 0-18 1 13,330 163 Disk heating up Helinm 69-F F 73.1-78.3 0-18 1 11,160 122 Disk heating up Helium 69-F F 73.1-78.3 0-18 1 9,880 87 Disk heating up Helium 69-F F 73.1-78.3 0-18 1 8,120 68 Disk heating up Helium 69-F Min 73.1-78.3 0-18 1 7,300 51 Disk heating up Helium 69-F T 73.1-78.3 0-18 1 10,140 46 Disk heating up Helium 69-F T 73.1-78.3 0-18 1 13,120 39 Disk heating up Helium 69-G F 14.3 0 1 13,160 306 Disk heating up 69-G F 14.3 0 0.16 10,200 303 Disk heating up 69-H F 14.3 -15 1 9,750 225 Disk heating up 69-H F 14.3 -15 0.16 7,680 222 Disk heating up 69-I F 14.3 -13 1 6,400 112 Disk heating up 69-I F 14.3 -13 0.16 5,070 110 Disk heating up 69-J F 74.2 10 1 21,750 277 Disk heating up Helium 69-J F 74.2 10 0.16 17,500 271 Disk heating up Helium 69-K F 74.2 2 1 16,340 196 Disk heating up Helium 69-K F 74.2 2 0.16 13,250 191 Disk heating up Helium 69-L F 77.7 2 1 12,370 110 Disk heating up Helium 69-L F 77.7 2 o.16 9,380 106 Disk heating up Helium Run 70 70-A F 14.1 - 9 11,270 320 Disk heating dn 70-A F 14.1 - 9 1 10,200 254 Disk heating dn 70-A F 14.1 - 9 1 9,410 209 Disk heating dn 70-A F 14.1 - 9 1 7,700 164 Disk heating dn 70-A F 14.1 - 9 1 7,200 130 Disk heating dn 70-A F 14.1 - 9 1 6,990 100 Disk heating dn 70-A F 14.1 - 9 1 6,510 77 Disk heating dn 70-A Min 14.1 - 9 1 4,400 60 Disk heating dn 70-A T 14.1 - 9 1 9,820 60 Disk heating dn 70-A T 14.1 - 9 1 15,890 43 Disk heating dn 70-B F 72.7-81.4 - 1- -4 1 16,580 288 Disk heating dn Nitrogen 70-B F 72.7-81.4 - 1- -4 1 14,470 231 Disk heating dn Nitrogen 70-B F 72.7-81.4 - 1- -4 1 14,000 185 Disk heating dn Nitrogen 70-B F 72.7-81.4 - 1- -4 1 13,600 153 Disk heating dn Nitrogen 70-B F 72.7-81.4 - 1 — -4 1 12,980 120 Disk heating dn Nitrogen 70-B F 72.7-81.4 - 1- -4 1 10,900 95 Disk heating dn Nitrogen 70-B F 72.7-81.4 - 1- -4 1 8,840 74 Disk heating dn Nitrogen 70-B Min 72.7-81.4 - 1- -4 1 8,280 56 Disk heating dn Nitrogen 70-B T 72.7-81.4 - 1- -4 1 15,390 44 Disk heating dn Nitrogen 70-C F 76.3 - 4 1 17,620 275 Disk heating dn Nitrogen 70-C F 76.3 - 4 0.16 14,710 269 Disk heating dn Nitrogen 70-D F 78.6 - 2 1 14,270 194 Disk heating dn Nitrogen 70-D F 78.6 - 2 0.16 12,600 189 Disk heating dn Nitrogen 70-E F 77.7 - 3 1 12,810 112 Disk heating dn Nitrogen 70-E F 77.7 - 3 0.16 11,290 107 Disk heating dn Nitrogen 70-F F 74.1 0-19 1 23,570 272 Disk heating dn Helium 70-F F 74.1 0-19 1 19,890 225 Disk heating dn Helium 70-F F 74.1 0-19 1 16,680 174 Disk heating dn Helium 70-F F 74.1 0-19 1 14,630 136 Disk heating dn Helium 70-F F 74.1 0-19 1 12,190 102 Disk heating dn Helium 70-F F 74.1 0-19 1 9,780 80 Disk heating dn Helium 70-F F 74.1 0-19 1 8,860 63 Disk heating dn Helium

174 Pressurizing Run Boiling a/g q/A T-Tsat Configuration Pressurizing Number Region Medium 70-G F 14.1 -10 1 12,730 305 Disk heating dn 70-G F 14.1 -10 0.16 10,700 301 Disk heating dn 70-H F 14.1 - 9 1 10,210 226 Disk heating dn 70-H F 14.1 - 9 0.16 8,720 222 Disk heating dn 70-I F 14.1 - 6 1 7,800 116 Disk heating dn 70-I F 14.1 - 6 0.16 6,850 113 Disk heating dn 70-3 F 78.6 15 1 24,040 275 Disk heating dn Helium 70-J F 78.6 15 0.16 18,380 268 Disk heating dn Helium 70-K F 72.2 3 1 16,040 195 Disk heating dn Helium 70-K F 72.2 3 0.16 14,200 190 Disk heating dn Helium 70-L F 75.2 2 1 13,780 113 Disk heating dn Helium 70-L F 75.2 2 0.16 11,430 108 Disk heating dn Helium Run 71 71-A F 14.3 - 8 1 12,960 305 Disk heating dn 71-A F 14.3 - 8 0 8,780 301 Disk heating dn 71-B F 14.3 - 9 1 9,860 226 Disk heating dn 71-B F 14.3 - 9 0 7,750 223 Disk heating dn 71-C F 14.3 - 8 1 7,630 114 Disk heating dn 71-C F 14.3 - 8 0 5,550 112 Disk heating dn 71-D F 14.3 - 7 1 12,960 308 Disk heating dn 71-D F 14.3 - 7 0 8,200 304 Disk heating dn 71-E F 14.3 0 1 10,050 226 Disk heating dn 71-E F 14.3 0 0 7,710 223 Disk heating dn 71-F F 14.3 1 1 7,240 116 Disk heating dn 71-F F 14.3 1 0 5,480 114 Disk heating dn 71-G F 74.3 0 1 16,900 276 Disk heating dn Nitrogen 71-G F 74.3 0 0 9,920 272 Dish heating dn Nitrogen 71-H F 74.3 2 1 14,580 197 Disk heating dn Nitrogen 71-H F 74.3 2 0 9,700 194 Disk heating dn Nitrogen 71-I F 76.3 4 1 27, 900 112 Disk heating dn Nitrogen 71-I F 76.3 4 0 15,410 103 Disk heating dn Nitrogen 71-J F 73.9 19 1 20,850 275 Disk heating dn Helium 71-J F 73.9 19 0 10, 590 269 Disk heating dn Helium 71-K F 73.3 7 1 16,750 195 Disk heating dn Helium 71-K F 73.3 7 0 11,590 190 Disk heating dn Helium 71-L F 76.3 8 1 17,900 111 Disk heating dn Helium 71-L F 76.3 8 0 15,380 105 Disk heating dn Helium 71-M F 73.8 17 1 21,900 277 Disk heating dn Helium 71-M F 73.8 17 0 15,420 270 Disk heating dn Helium 71-N F 73.6 13 1 19,440 199 Disk heating dn Helium 71-N F 73.6 13 0 13,300 193 Disk heating dn Helium 71-0 F 81.3 5 1 13,560 110 Disk heating dn Helium 71-0 F 81.3 5 0 10,220 106 Disk heating dn Helium Run 72 72-A F 14.3 - 1 1 6,820 240 1/4-inch sphere 72-A F 14.3 - 1 1 6,100 220 1/4-inch sphere 72-A F 14.3 - 1 1 5,650 205 1/4-inch sphere 72-B F 14.3 0 (EST) 1 5,000 180 1/4-inch sphere 72-B F 14.3 0 (EST) 1 4,560 160 1/4-inch sphere 72-B F 14.3 0 (EST) 1 4,280 150 1/4-inch sphere 72-B F 14.3 0 (EST) 1 3,820 140 1/4-inch sphere 72-C F 14.3 - 1 1 3,110 86 1/4-inch sphere 72-C F 14.3 - 1 1 2,960 76 1/4-inch sphere 72-C F 14.3 - 1 1 2,760 66 1/4-inch sphere

175 Run Boiling Pressure Subcooling a/g q/A T-T Coniguration Pressurizing Number Region sat Medium 72-C F 14.3 - 1 1 2,596 56 1/4-inch sphere 72-C Min 14.3 - 1 1 2,560 46 1/4-inch sphere 72-C T 14.3 - 1 1 2,800 36 1-4-inch sphere 72-C T 14.3 - 1 1 6,990 31 1/4-inch sphere 72-C T 14.3 - 1 1 18,010 27 1/4-inch sphere 72-C Max 14.3 - 1 1 39,150 17 1/4-inch sphere 72-C N 14.3 - 1 1 24,820 12 1/4-inch sphere 72-C N 14.3 - 1 1 10,750 9 1/4-inch sphere 72-D F 46.8 0 1 4,030 70 1/4-inch sphere Nitrogen 72-D Min 46.8 0 1 3,720 55 1/4-inch sphere Nitrogen 72-D T 46.8 0 1 8,310 36.5 1/4-inch sphere Nitrogen 72-D T 46.8 0 1 10,610 34.4 1/4-inch sphere Nitrogen 72-D T 46.8 0 1 16,230 30.6 1/4-inch sphere Nitrogen 72-D T 46.8 0 1 25,310 27.0 1/4-inch sphere Nitrogen 72-D T 46.8 0 1 36.480 23.5 1/4-inch sphere Nitrogen 72-D T 46.8 0 1 48,880 18.4 1/4-inch sphere Nitrogen 72-D T 46.8 0 1 55,960 15.8 1/4-inch sphere Nitrogen 72-D Max 46.8 0 1 59,460 12.8 1/4-inch sphere Nitrogen 72-D N 46.8 0 1 54,710 11.2 1/4-inch sphere Nitrogen 72-D N 46.8 0 1 46,o60 9.8 1/4-inch sphere Nitrogen 72-D N 46.8 0 1 37,270 8.7 1/4-inch sphere Nitrogen 72-D N 46.8 0 1 26,960 7.8 1/4-inch sphere Nitrogen 72-D N 46.8 0 1 18,860 7.5 1/4-inch sphere Nitrogen 72-D N 46.8 0 1 14,320 7.2 1/4-inch sphere Nitrogen 72-D N 46.8 0 1 10,140 6.5 1/4-inch sphere Nitrogen 72-E F 46.1 0 1 8,480 225 1/4-inch sphere Nitrogen 72-E F 46.1 0 1 7,980 210 1/4-inch sphere Nitrogen 72-E F 46.1 0 1 7,140 185 1/4-inch sphere Nitrogen 72-F F 45.1 0 1 6,900 165 1/4-inch sphere Nitrogen 72-F F 45.1 0 1 6,0o60 145 1/4-inch sphere Nitrogen 72-F F 45.1 0 1 5 390 120 1/4-inch sphere Nitrogen 72-G F 75.5 0 1 8,150 160 1/4-inch sphere Nitrogen 72-G F 75.5 0 1 7,120 140 1/4-inch sphere Nitrogen 72-G F 75.5 0 1 6,350 125 1/4-inch sphere Nitrogen 72-G F 75.5 0 1 5,980 110 1/4-inch sphere Nitrogen 72-H F 74.7 0 1 4,560 70 1/4-inch sphere Nitrogen 72-H F 74.7 0 1 4,140 55 1/4-inch sphere Nitrogen 72-H Min 74.7 0 1 3,950 40 1/4-inch sphere Nitrogen 72-I F 14.3 0 1 6,990 250 1/4-inch sphere 72-I F 14.3 0 1 6,550 243 1/4-inch sphere 72-I F 14.3 0 1 6,510 233 1/4-inch sphere 72-I F 14.3 0 0 3,000 227 1/4-inch sphere 72-I F 14.3 0 0 3,130 223 1/4-inch sphere 72-J F 14.3 0 1 5,230 179 1/4-inch sphere 72-J F 14.3 0 1 4,720 167 1/4-inch sphere 72-J F 14.3 0 0 2,480 158 1/4-inch sphere 72-K F 14.3 0 1 2,850 71 1/4-inch sphere 72-K Min 14.3 0 1 2,400 51 1/4-inch sphere 72-K T 14.3 0 1 4,420 43 1/4-inch sphere 72-K T 14.3 0 0 5,000 41 1/4-inch sphere 72-K T 14.3 0 0 1,390 38.5 1/4-inch sphere 72-K T 14.3 0 0 3,390 36.8 1/4-inch sphere 72-K T 14.3 0 0 9,750 32.1 1/4-inch sphere 72-K T 14.3 0 0 21,220 27.5 1/4-inch sphere 72-L F 14.3 1 1 3,140 72 1/4-inch sphere 72-L Min 14.3 1 1 2,720 55 1/4-inch sphere 72-L T 14.3 1 1 3,030 38 1/4-inch sphere

176 Run Boiling Pressure Subcooling a/g q/A T-Tsat ConigPressurizing Number Region Medium 72-L T 14.3 1 0 1,800 35 1/4-inch sphere 72-L T 14.3 1 0 1,290 31 -inch sphere 72-M F 14.3 - 1 1 2,900 78 1/4-inch sphere 72-M F 14.3 - 1 1 2,500 61 1/4-inch sphere 72-M Min 14.3 - 1 1 2,360 43 1/4-inch sphere 72-M T 14.3 - 1 0 735 35 1/4-inch sphere 72-M T 14.3 - 1 0 1,650 33 1/4-inch sphere 72-N F 44.3 12 1 10,780 223 1/4-inch sphere Helium 72-N F 44.3 12 1 10,270 209 1/4-inch sphere Helium 72-N F 44.3 12 1 9,760 203 1/4-inch sphere Helium 72-N F 44.3 12 0 3,410 191 1/4-inch sphere Helium 72-0 F 44.3 14 (EST) 1 8,340 161 1/4-inch sphere Helium 72-0 F 44.3 14 (EST) 1 7,770 151 1/4-inch sphere Helium 72-0 F 44.3 14 (EST) 0 4,290 136 1/4-inch sphere Helium 72-0 F 44.3 14 (EST) O 3,350 133 1/4-inch sphere Helium 72-P Min 44.3 14 1 5,990 66 1/4-inch sphere Helium 72-P T 44.3 14 1 7,010 37 1/4-inch sphere Helium 72-P T 44.3 14 1 20,890 31 1/4-inch sphere Helium 72-P T 44.3 14 1 48,300 19.9 1/4-inch sphere Helium 72-P Max 44.3 14 0 61,330 14.1 1/4-inch sphere Helium 72-P N 44.3 14 0 39,300 8.9 1/4-inch sphere Helium 72-P N 44.3 14 0 17,560 4.7 1/4-inch sphere Helium 72-Q Min 44.6 12 1 7,080 70 1/4-inch sphere Helium 72-Q T 44.6 12 1 10,760 46 1/4-inch sphere Helium 72-Q T 44.6 12 1 36,890 31 1/4-inch sphere Helium 72-Q Max 44.6 12 0 61,730 21 1/4-inch sphere Helium 72-Q N 44.6 12 0 40,630 12.3 1/4-inch sphere Helium 72-Q N 44.6 12 0 13,470 7.0 1/4-inch sphere Helium 72-R Min 43.7 12 (EST) 1 7,120 71 1/4-inch sphere Helium 72-R T 43.7 12 (EST) 1 14,760 41 1/4-inch sphere Helium 72-R T 43.7 12 (EST) 0 32,360 29 1/4-inch sphere Helium 72-R T 43.7 12 (EST) 0 33,810 22 1/4-inch sphere Helium 72-R Max 43.7 12 (EST) 0 37,430 12.8 1/4-inch sphere Helium 72-R N 43.7 12 (EST) 0 24,350 8.9 1/4-inch sphere Helium 72-R N 43.7 12 (EST) O 17,370 7.5 1/4-inch sphere Helium 72-S F 43.8 11 1 6,200 76 1/4-inch sphere Helium 72-S Min 43.8 11 1 5,540 58 1/4-inch sphere Helium 72-S T 43.8 11 0 5,520 51 1/4-inch sphere Helium 72-S T 43.8 11 0 8,920 41 1/4-inch sphere Helium 72-S T 43.8 11 0 14,190 39 1/4-inch sphere Helium 72-S T 43.8 11 0 22,470 36 1/4-inch sphere Helium 72-T Min 14.3 - 1 1 2,910 70 1/4-inch sphere 72-T T 14.3 - 1 1 2,920 50 1/4-inch sphere 72-T T 14.3 - 1 1 3,240 40 1/4-inch sphere 72-T T 14.3 - 1 1 4,020 37 1/4-inch sphere 72-T T 14.3 1 1 11,060 31 1/4-inch sphere 72-T T 14.3 - 1 0 19,510 21 1/4-inch sphere 72-T Max 14.3 -1 0 22,660 12.3 1/4-inch sphere 72-T N 14.3 - 1 0 8,920 8.5 1/4-inch sphere Run 73 73-A T 76.0 - 2 1 12,500 35 1-inch sphere Nitrogen 73-A T 76.0 - 2 1 44,430 28 1-inch sphere Nitrogen 73-A Max 76.0 - 2 1 76,590 19.5 l-inch sphere Nitrogen 73-A N 76.0 - 2 1 46,740 14.2 l-inch sphere Nitrogen 73-A N 76.0 - 2 1 6,480 7.5 l-inch sphere Nitrogen 73-A N 76.0 - 2 1 1,130 3.7 l-inch sphere Nitrogen

177 Run Boiling Pressurizing Run Boiling Pressure Subcooling a/g q/A T-Tsat Configurationg Number Region Medium 73-B T 75.0 - 3 1 3,000 40 1-inch sphere Nitrogen 73-B T 75.0 - 3 1 13,240 37.5 1-inch sphere Nitrogen 73-B T 75.0 - 3 1 39,110 30.4 1-inch sphere Nitrogen 73-B Max 75.0'- 3 1 77,530 20.8 1-inch sphere Nitrogen 73-B N 75.0 - 3 1 51,430 15.1 1-inch sphere Nitrogen 73-B N 75.0 - 3 1 6,570 7.1 1-inch sphere Nitrogen 73-B N 75.0 - 3 1 1,200 3.9 1-inch sphere Nitrogen 73-C T 45.0 - 4 1 6,880 42 1-inch sphere Nitrogen 73-C T 45.0 - 4 1 13,920 39 1-inch sphere Nitrogen 73-C T 45.0 - 4 1 23,380 36 1-inch sphere Nitrogen 73-C T 45.0 - 4 1 39,660 30 1-inch sphere Nitrogen 73-C T 45.0 - 4 1 56,630 26 1-inch wphere Nitrogen 73-C Max 45.0 - 4 1 66,500 23 1-inch sphere Nitrogen 73-C N 45.0 - 4 1 56,090 19 1-inch sphere Nitrogen 73-C N 45.o - 4 1 44,750 17.7 1-inch sphere Nitrogen 73-C N 45.0 - 4 1 24,930 14.7 1-inch sphere Nitrogen 73-C N 45.0 - 4 1 12,830 12.5 1-inch sphere Nitrogen 73-C N 45.0 - 4 1 6,030 10.2 1-inch sphere Nitrogen 73-C N 45.0 - 4 1 3,190 8.1 1-inch sphere Nitrogen 73-C N 45.0 - 4 1 1,180 5.7 1-inch sphere Nitrogen 73-D F 79.0 - 2 1 5,900 153 1-inch sphere Nitrogen 73-D F 79.0 - 2 1 5,630 140 1-inch sphere Nitrogen 73-D F 79.0 - 2 1 5,350 127 1-inch sphere Nitrogen 73-D F 79.0 - 2 1 4,730 115 1-inch sphere Nitrogen Run 75 75-A F 44.3 0 1 18,600 331 Vertical disk Helium 75-A F 44.3 0 1 16,400 291 Vertical disk Helium 75-A F 44.3 0 1 13,820 251 Vertical disk Helium 75-A F 44.3 0 1 12,060 211 Vertical disk Helium 75-A F 44.3 0 1 10,680 171 Vertical disk Helium 75-A F 44.3 0 1 8, 630 131 Vertical disk Helium 75-A F 44.3 0 1 7,480 91 Vertical disk Helium 75-A F 44.3 0 1 6,530 71 Vertical disk Helium 75-A F 44.3 0 1 5,080 51 Vertical disk Helium 75-B F 44.3 0 1 16,220 301 Vertical disk Nitrogen 75-B F 44.3 0 1 14, 420 261 Vertical disk Nitrogen 75-B F 44.3 0 1 12,420 221 Vertical disk Nitrogen 75-B F 44.3 0 1 10,810 181 Vertical disk Nitrogen 75-B F 44.3 0 1 10,000 141 Vertical disk Nitrogen 75-B F 44.3 0 1 7,280 101 Vertical disk Nitrogen 75-B F 44.3 0 1 6,295 81 Vertical disk Nitrogen 75-B F 44.3 0 1 5,850 61 Vertical disk Nitrogen 75-C F 74.3 0 1 17,950 310 Vertical disk Nitrogen 75-C F 74.3 0 1 17,200 270 Vertical disk Nitrogen 75-C F 74.3 0 1 13,020 210 Vertical disk Nitrogen 75-C F 74.3 0 1 11,620 170 Vertical disk Nitrogen 75-C F 74.3 0 1 9,880 130 Vertical disk Nitrogen 75-C F 74.3 0 1 8,930 110 Vertical disk Nitrogen 75-C F 74.3 0 1 7,750 90 Vertical-disk Nitrogen 75-C F 74.3 0 1 7,235 70 Vertical disk Nitrogen 75-C F 74.3 0 1 6,200 50 Vertical disk Nitrogen 75-D F 73.9 0 1 17,570 310 Vertical disk Helium 75-D F 73.9 0 1 16,570 270 Vertical disk Helium 75-D F 73.9 0 1 14,800 230 Vertical disk Helium 75-D F 73.9 0 1 12,800 190 Vertical disk Helium

178 Run Boiling Pressure Subcooling a/g q/A T-Tsat Pressuration Medium Number Region Medium 75-D F 73.9 0 1 10,720 150 Vertical disk Helium 75-D F 73.9 0 1 9,100 110 Vertical disk Helium 75-D F 73.9 0 1 7,610 70 Vertical disk Helium 75-D F 73.9 0 1 6,630 50 Vertical disk Helium 75-E F 77.0 - 1 1 7,790 125 Disk heating up Nitrogen 75-E F 77.0 - 1 1 6,750 112 Disk heating up Nitrogen 75-E F 77.0 - 1 0 6,180 o10 Disk heating up Nitrogen 75-E F 77.0 - 1 0 2,285 108.5 Disk heating up Nitrogen 75-F F 78.3 0 1 11,710 274 Disk heating dn Nitrogen 75-F F 78.3 0 0 lO, 680 269 Disk heating dn Nitrogen 75-G F 73.7 0 1 10,500 198 Disk heating dn Nitrogen 75-G F 73.7 0 0 9,680 193 Disk heating dn Nitrogen 75-H F 74.3 - 1 1 8,100 124 Disk heating dn Nitrogen 75-H F 74.3 - 1 1 7,400 119 Disk heating dn Nitrogen 75-H F 74.3 - 1 1 7,420 115 Disk heating dn Nitrogen 75-H F 74.3 - 1 0 7,500 111.5 Disk heating dn Nitrogen 75-H F 74.3 - 1 0 6,635 110.5 Disk heating dn Nitrogen 75-I F 73.9 - 2 1 16,400 238 Vertical disk Nitrogen 75-I F 73.9 - 2 0 10,800 234 Vertical disk Nitrogen 75-J F 52 2 1 48,220 98 Vertical disk Nitrogen 75-J F 52 2 0.16 39,900 82 Vertical disk Nitrogen 75-K Min 44.3 1 1 15,200 70 Vertical disk Nitrogen 75-K T 44.3 1 1 15,900 60 Vertical disk Nitrogen 75-K T 44.3 1 1 16,600 50 Vertical disk Nitrogen 75-K T 44.3 1 1 16,940 41 Vertical disk Nitrogen 75-K T 44.3 1 1 33,710 31 Vertical disk Nitrogen 75-K T 44.3 1 1 62,520 21 Vertical disk Nitrogen 75-K Max 44.3 1 1 84,390 16.2 Vertical disk Nitrogen 75-K N 44.3 1 1 54,520 13 Vertical disk Nitrogen 75-K N 44.3 1 1 28,890 10 Vertical disk Nitrogen 75-K N 44.3 1 1 10,750 7 Vertical disk Nitrogen 75-K N 44.3 1 1 3,170 3.7 Vertical disk Nitrogen 75-K N 44.3 1 1 889 1.4 Vertical disk Nitrogen 75-L F 44.3 - 1 1 15,650 270 Vertical disk Nitrogen 75-L F 44.3 - 1 1 14,000 200 Vertical disk Nitrogen 75-L F 44.3 - 1 1 11,560 150 Vertical disk Nitrogen 75-L F 44.3 - 1 1 9,190 100 Vertical disk Nitrogen 75-L F 44.3 - 1 1 6,840 60 Vertical disk Nitrogen Run 76 76-A F 76.6 - 1 1 5,470 63 1/4-inch sphere Nitrogen 76-A Min 76.6 - 1 1 4,950 47 1/4-inch sphere Nitrogen 76-A T 76.6 - 1 1 5,070 34 1/4-inch sphere Nitrogen 76-A T 76.6 - 1 0.17 9,330 30 1/4-inch sphere Nitrogen 76-A T 76.6 - 1 0.17 21,140 24 1/4-inch sphere Nitrogen 76-A T 76.6 - 1 0.17 44,690 16.4 1/4-inch sphere Nitrogen 76-A Max 76.6 - 1 0.17 74,460 13.6 1/4-inch sphere Nitrogen 76-A N 76.6 - 1 0.17 34,470 10.6 1/4-inch sphere Nitrogen 76-A N 76.6 - 1 0.17 9,010 6.3 1/4-inch sphere Nitrogen 76-B F 44.6 - 2 1 5,030 76 1/4-inch sphere Nitrogen 76-B F 44.6 - 2 1 4,380 66 1/4-inch sphere Nitrogen 76-B F 44.6 - 2 1 3,640 56 1/4-inch sphere Nitrogen 76-B F 44.6 - 2 1 3,890 46 l/4-inch sphere Nitrogen 76-B Min 44.6 - 2 1 3,020 40 1/4-inch sphere Nitrogen 76-B T 44.6 - 2 0.17 4,830 37 1/4-inch sphere Nitrogen 76-B T 44.6 - 2 0.17 9,100 30 1/4-inch sphere Nitrogen

179 Run Boilzing Pressure Subcooling a/g q/A T-Tsat Configuration Number Region Medium 76-B T 44.6 - 2 0.17 33,190 22 1/4-inch sphere Nitrogen 76-B T 44.6 - 2 0.17 42,140 15.5 1/4-inch sphere Nitrogen 76-B Max 44.6 - 2 0.17 43,150 12.7 1/4-inch sphere Nitrogen 76-B N 44.6 - 2 0.17 23,410 10.0 1/4-inch sphere Nitrogen 76-B N 44.6 - 2 0.17 4,390 6.5 1/4-inch sphere Nitrogen 76-B N 44.6 - 2 0.17 3,060 5.1 1/4-inch sphere Nitrogen 76-C F 73.9 - 2 1 5,080 65 1/4-inch sphere Nitrogen 76-C F 73.9 - 2 1 4,610 50 1/4-inch sphere Nitrogen 76-C Min 73.9 - 2 1 4,460 40 1/4-inch sphere Nitrogen 76-C T 73.9 - 2 1 15,940 30 1/4-inch sphere Nitrogen 76-C T 73.9 - 2 1 41,830 20 1/4-inch sphere Nitrogen 76-C Max 73.9 - 2 1 99,730 15.7 1/4-inch sphere Nitrogen 76-C N 73.9 - 2 1 43,980 11.7 1/4-inch sphere Nitrogen 76-C N 73.9 - 2 1 10,680 5.9 1/4-inch sphere Nitrogen 76-D F 76.1 - 1 1 5,090 64 1/4-inch sphere Nitrogen 76-D Min 76.1 - 1 1 4,910 49 1/4-inch sphere Nitrogen 76-D T 76.1 -1 1 6,010 36 1/4-inch sphere Nitrogen 76-D T 76.1 - 1 0 10,150 31 1/4-inch sphere Nitrogen 76-D T 76.1 - 1 0 24,910 26 1/4-inch sphere Nitrogen 76-D Max 76.1 - 1 0 46,420 16.3 1/4-inch sphere Nitrogen 76-D N 76.1 - 1 0 32,140 12.3 1/4-inch sphere Nitrogen 76-D N 76.1 - 1 0 12,550 8.5 1/4-inch sphere Nitrogen 76-E F 46.3 - 1 1 4,300 71 1/4-inch sphere Nitrogen 76-E Min 46.3 - 1 1 4,090 51 1/4-inch sphere Nitrogen 76-E T 46.3 - 1 1 7,140 37 1/4-inch sphere Nitrogen 76-E T 46.3 - 1 0 3,180 34 1/4-inch sphere Nitrogen 76-E T 46.3 - 1 0 10,320 31 1/4-inch sphere Nitrogen 76-E T 46.3 - 1 0 19,340 22 1/4-inch sphere Nitrogen 76-E Max 46.3 - 1 0 20,550 11.3 1/4-inch sphere Nitrogen Run 77 77-A F 72.3 0 1 3,540 65 1-inch sphere Nitrogen 77-A F 72.3 0 1 3,180 50 1-inch sphere Nitrogen 77-A T 72.3 0 0 8,520 28 1-inch sphere Nitrogen 77-B F 77.1 0 1 2,960 47 1-inch sphere Nitrogen 77-B Min 77.1 0 1 2,840 43 1-inch sphere Nitrogen 77-B T 77.1 0 0 12,500 30 1-inch sphere Nitrogen 77-C Min 77.8 0 1 3,190 47 1-inch sphere Nitrogen 77-C T 77.8 0 1 3,370 42 1-inch sphere Nitrogen 77-C T 77.8 0 1 15,740 38 1-inch sphere Nitrogen 77-C T 77.8 0 1 42,980 27 1-inch sphere Nitrogen 77-C Max 77.8 0 1 76,560 21 1-inch sphere Nitrogen 77-C N 77.8 0 1 49,070 14.7 1-inch sphere Nitrogen 77-C N 77.8 0 1 24,990 11.7 1-inch sphere Nitrogen 77-D Min 73.7 0 1 3,060 48 1-inch sphere Nitrogen 77-D T 73.7 0 1 3,380 40 1-inch sphere Nitrogen 77-D T 73.7 0 1 12,400 36 1-inch sphere Nitrogen 77-D T 73.7 0 0 14$,450 30 1-inch sphere Nitrogen 77-D T 73.7 0 0 8,990 28 1-inch sphere Nitrogen 77-D T 73.7 0 0 6,34o 27 1-inch sphere Nitrogen 77-D T 73.7 0 0 4,770 26 1-inch sphere Nitrogen 77-E Min 74.2 0 1 3,000 44 1-inch sphere Nitrogen 77-E T 74.2 0 1 9,820 35 1-inch sphere Nitrogen 77-E T 74.2 0 1 47,520 27 1-inch sphere Nitrogen 77-E T 74.2 0 0 49,980 26 1-inch sphere Nitrogen 77-E T 74.2 0 0 30,760 23.4 1-inch sphere Nitrogen 77-E T 74.2 0 0 15,920 21.4 l-inch sphere Nitrogen....~~~~~~~~~~~~~~~itoe

18o Run Boiling Pressure Subcooling a/g q/A T-T Configuration Pressurizing Number Region Medium 77-E T 74.2 0 0 22,430 19.4 1-inch sphere Nitrogen 77-E Max 74.2 0 0 25,550 17.9 1-inch sphere Nitrogen 77-E N 74.2 0 0 22,480 13.4 i-inch sphere Nitrogen 77-E N 74.2 0 0 17,030 9.9 1-inch sphere Nitrogen 77-F Min 44.1 0 1 2,580 49 1-inch sphere Nitrogen 77-F T 44.1 0 1 5,270 39 l-inch sphere Nitrogen 77-F T 44.1 0 1 12,830 36 1-inch sphere Nitrogen 77-F T 44.1 0 1 19,090 32 1-inch sphere Nitrogen 77-F T 44.1 0 0 29,140 29 1-inch sphere Nitrogen 77-F T 44.1 0 0 23,200 27.4 1-inch sphere Nitrogen 77-F T 44.1 0 0 17, 500 26.2 1-inch sphere Nitrogen 77-F T 44.1 0 0 5,930 24.6 1-inch sphere Nitrogen 77-G T 43.4 0 1 3,680 43 1-inch sphere Nitrogen 77-G T 43.4 0 1 9,610 39 1-inch sphere Nitrogen 77-G T 43.4 0 1 21,820 34.5 1-inch sphere Nitrogen 77-G T 43.4 0 1 58,000 25.4 1-inch sphere Nitrogen 77-G T 43.4 0 0 45,570 21.1 1-inch sphere Nitrogen 77-G T 43.4 0 0 10,170 19.7 1-inch sphere Nitrogen 77-G T 43.4 0 0 1,230 19.2 1-inch sphere Nitrogen 77-G T 43.4 0 0 17,980 18.4 1-inch sphere Nitrogen 77-G Max 43.4 0 0 18, 990 15.5 1-inch sphere Nitrogen 77-G N 43.4 0 0 18,710 12.1 1-inch sphere Nitrogen 77-G N 43.4 0 0 13,450 10.5 1-inch sphere Nitrogen 77-G N 43.4 0 0 9,440 9.9 1-inch sphere Nitrogen 77-H F 74.2 0 1 3,150 48 1-inch sphere Nitrogen 77-H Min 74.2 0 1 2,580 40 1-inch sphere Nitrogen 77-H T 74.2 0 1 22,v790 31.4 1-inch sphere Nitrogen 77-H T 74.2 0 0.17 13,570 29.6 1-inch sphere Nitrogen 77-H T 74.2 0 0.17 6,910 29 1-inch sphere Nitrogen 77-H T 74.2 0 0.17 17,460 27 1-inch sphere Nitrogen 77-H T 74.2 0 0.17 39,160 21.4 1-inch sphere Nitrogen 77-H Max 74.2 0 0.17 53,380 18 1-inch sphere Nitrogen 77-H N 74.2 0 0.17 38,0o60 13.9 1-inch sphere Nitrogen 77-I T 44.0 0 1 2,660 46.5 1-inch sphere Nitrogen 77-I T 44.0 0 1 7,850 37.8 1-inch sphere Nitrogen 77-I T 44.0 0 1 15,790 34.2 1-inch sphere Nitrogen 77-I T 44.0 0 1 26, 540 31.1 1-inch sphere Nitrogen 77-I T 44.o 0 0.17 45,44o 25.6 1-inch sphere Nitrogen 77-I T 44.0 0 0.17 40,350 23.7 1-inch sphere Nitrogen 77-I T 44.0 o 0.17 19,970 22.7 1-inch sphere Nitrogen 77-I T 44.0 0 0.17 33,700 21.15 1-inch sphere Nitrogen 77-I T 44.0 0 0.17 56160 21.05 1-inch sphere Nitrogen 77-I Max 44.0 0 0.17 76,390 19.2 1-inch sphere Nitrogen 77-I N 44.o 0 0.17 50,730 17.1 1-inch sphere Nitrogen 77-I N 44.0 0 0.17 30,880 14.2 1-inch sphere Nitrogen 77-I N 44.o0 0.17 13,290 11.5 1-inch sphere Nitrogen 77-I N 44.0 0 0.17 8,190 10.6 1-inch sphere Nitrogen 77-:I N 44.o 0 0.17 3,901 9.2 1-inch sphere Nitrogen

181 2. SAMPLE PHOTOGRAPHS One representative frame print is presented for each test surface and level of ATsat for which photographs were obtained. Irregularly shaped dark object at right center of photographs in Figs. A-1 through A-4 is spacer between inner and outer walls of transparent dewar. Wire frameworks beside test surfaces provided absolute measurement reference.

182 Measurement Reference AT 100= F sat ATsat F sat ATsat = 200~F ATsat - 3500~ 1-inch diameter sphere Saturated liquid P = attm (a/g) = 1 Fig. A-1. Photographs of film boiling on a sphere.

183 Tsat = 1000F ATsat = 2000F AT 300OF ATsat 3-inch Diameter Vertical Disk 0.500 9 ~500 ~Saturated Liquid P = 1 attm (a/g) = 1 Fig. A-2. Photographs of film boiling on a vertical disk.

Measurement Reference ATsat 100~F ATsat = 0~F ATsat = 200~F ATsat = 300~F 3-inch diameter horizontal disk Heating up'~ 0.500 g Saturated liquid P = i atm (a/g) = 1 Fig. A-3. Photographs of film boiling on a horizontal disk heating up.

185 ATsat = 100~F ATsat = 200OF ATsat = 300~F 3-inch diameter horizontal disk Heating down -by re0.500 fig Saturated liquid P =l am (a/g) = 1 Fig. A-4. Photographs of film boiling on a horizontal disk heating down.

186 3. REDUCED PHOTOGRAPHIC DATA Column Headings: ATsat: in ~F Frame Number: for identification purposes Separation Point-R: angular location above which vapor no longer flows along the sphere surface, right side Separation Point —L: angular location above which vapor no longer flows along the sphere surface, left side Film Thickness at Angular Location: film thickness in inches, angular location in degrees clockwise from top of sphere Position: distance in inches from bottom of vertical plate or left side of horizontal plate Film Thickness: in inches

1-INCH DIAMETER SPHERE Frame Separation Separation Film Thickness'at Angular Location Asat No.- Point-R Point-L N'O 60~' 9O0 130~0 16o 200~23 2700 30 lO0~, 1 31 38.04o.018.019.013.017.026.018.028.02.0 2 1OO0 2 30~0 325~.027.028.023 ~ 013.008.017.018 ~ 019.02 Ole, 100~ 3 45 o 305 ~.115.O18.02 3.009..008 ~ 009.018.O14.08-12 2000~ 200o 300 o.027 ~ O19 O.008.013 018 ~ 019.026 2000 2 290 335~0.028 ~ 037.017 ~ 013.017.018.o14 ~ 035 2000o 42~305.028.02 3 O.08.009 ~ 009 ~ 019.026 2000~ 8~ 340~.028 ol. O1 ~009.013 ~ 009.018.028.02 300~ 5 o 3320 o ~035 ~ 035.014.013.0O17.017.018.027.044 3000 2 z z ~ 331~.0o52.0oz7. o55.013.0o25.017.0o27.036.08.3 3000 3 300 3o 8 o o17 o017 o055 026034 o1 06036.027 3000~ 210 3160o.078.026.045.0o17.025 034.o18.027.044.3 3000~ 380 3200.322.009.04.0o17.034.3 07.3 05.5

188 VERTICAL DISK Frame Experimental Measurements ATsat No. 1 2 3 4 5 6 1000 1 Position.12.63 1.12 1,85 2.37 100~ Film Thickness.029.0o48.058.096.077 100~ 2 Position.96 1.05 1.31 2.46 2.78 100~ Film Thickness.058.067.087.096.087 1000 Position.30 1.47 1.58 2.31 100 3 Film Thickness.058.067.077.087 1000 Position.50.77 2.21 2.56 1000 Film Thickness.058.058.087.106 200~ Position.1.76 1.42 2.13 2.54 200~ Film Thickness.035.o069g.o86.173.155 2000 Position.22.62 ~93 1 55 2.70 200~ Film Thickness.052.052.0o69.o86.147 200~ Position.43 1.22 1.75 1.89 2.46 200~ Film Thickness.0o43 1078.095.121.112 2000 Position.51.84 2.05 2.47 2.84 2000 Film Thickness.061.o86.130.138.156 2000 Position.24 1.10 1.28 1.36 2.63 200~ Film Thickness.043.078.078.112.155 3000 1 Position.14.52 1.08 1.38 2.35 300~ Film Thickness.102.092.092 ~133.153 3000~ Position.89 1.27 1.55 1.97 2.29 3000 Film Thickness.072.082.102.112.112 3000 Position. 37 49.73 1.16 1.69 2.16 300~ Film Thickness.051.061.051.082.072.143 3000 4 Position 1 46 1.83 2.42 2.68 2.83 300~ Film Thickness.061. 133.173.173.163 3000 Position.81 1.01 1.76 2.10 2.71 3000 Film Thickness.061 0 061.092.102

189 HORIZONTAL DISK HEATING UP Frame Experimental Measurements Tsat No. 1 2 3 4 5 6 100 0 Position.11 1.08 2.11 2.66 100o 0 Film Thickness.033.022.028.028 1000 2 Position.71 1.68 1.94 2.59 2.83 100~ Film Thickness.044.039.039.033.039 100~ Position.19 1.28 1.58 1.99 100~ 3 Film Thickness.033.028.044.028 100~ Position.42.98 1.79 2.15 1000 Film Thickness.022.033.044.033 100~ Position.86 1.15 1.72 2.06 2.40 100o Film Thickness.0o44.022.033.033.056 2000 Position.14.96 1.29 1.88 2.78 200 1 Film Thickness.122.089.111.133.167 200~ Position.45.88 1.54 2.20 2.69 200 2 Film Thickness.144.167.167.189.178 2000 Position.53 1.03 1.85 2.73 2.97 200~ 3 Film Thickness.111.156.178.144.122 2000 4 Position.45.91 1.16 1.74 2.12 2.86 2000 Film Thickness.100.100.089.122.122.100 2000 Position.35.84 1.18 2.03 2.90 2000 Film Thickness.0o6.122.089.os6.078 3000 1 Position.95 1.25 1.62 2.24 2.93 300~ Film Thickness o066.082.082.106.066 300~ Position.32 1.01 1.40 1.54 2.49 300 Film Thickness.090.074.098.066.082 300 Position.89 1.05 1.69 2.35 2.65 3000 Film Thickness.098.041.066.057.098 300 4 Position.20.85 1.46 2.41 2.70 300~ Film Thickness.057.057.098.082.049 3000~ Position.45.80 1.44 2.15 2.56 300~ Film Thickness.090.090.082.106.115

190 HORIZONTAL DISK HEATING DOWN Frame Experimental Measurements ATsat No. 1 2 3 4 5 1000 Position.67 1.26 1.79 2.33 2.89 100~ 1Film Thickness.0.049.049.057 100~ Position.52 1.11 1.67 2.18 2.74 100~ 2 Film Thickness.041.033.041.041.041 1000 Position.38.99 1.56 2.08 2.65 100~ 3 Film Thickness.041.041.041.041.041 100 4 Position.25.88 1.47 1.99 2.54 1000 Film Thickness.062.029.041.041.L45 100 ~ Position.07.77 1.36 2.44 2.82 100~ Film Thickness.066.041.037.045.049 200 Position.29 1.02 1.65 2.29 2.88 2000 Film Thickness.029.041.o49.41.041 033 2000 Position.15.92 1.52 1.97 2.76 2000 Film Thickness.029.037.041.037.029 200 3 Position.40 1.11 1.75 2.35 2.95 2000 Film Thickness.041.053.053.049.041 200 4 Position.48 1.20 1.84 2.40 2.68 2000 Film Thickness.037.057.057.0o4.o4i 200~ Position.61.77 1.33 1.96 2.52 200~ Film Thickness.033.041. 053.049.o41 300~ Position 61 1.17 1.92 2 40 2.91 3000 Film Thickness.058.053.058.053.053 300~ Position.47 1.07 1.76 2.28 2.80 300~ Film Thickness. 053.08.069.062.077 300~ Position.39.96 1.64 2.18 2.70 300o Film Thickness.062.062.069.062 053 3000 4 Position ~ 28.83 1.51 2.10 2.61 3000 Film Thickness.062.058.053 058.053 3000 Position.10.74 1.39 2.02 2.54 300~ Film Thickness.053.058.053.o6s 062 3000 6 Position.21.68 1.28 1.84 2.47 300~ Film Thickness.058.062.062.0o6.062

APPENDIX B ANALYSIS OF THE FILM THICKNESS ON A FLAT PLATE HEATING DOWN The physical model used to analyze film thickness on a flat plate heating down assumes a finite dimension for the flat plate. Infinite horizontal dimensions for the flat plate reduce the problem to that presented in Section VII.A.3.a, i.e., film formation at zero gravity. Finite dimensions result in flow of the vapor parallel as well as normal to the plate. If the plate is finite in one direction only, the flow is two-dimensional; if it is finite in two directions, the flow is three-dimensional. The general analysis of the problem requires the simultaneous solution of both the energy and the momentum equations. This would give the temperature and velocity distributions, along with the vapor film thickness. An estimation of the deviation of the liquid-vapor interface from a true horizontal is possible by considering the momentum equation alone, using an assumed velocity profile in the vapor film. Several different models are possible. The simplest model, Model I, utilizes a plate which is finite in one direction and has a uniform velocity profile in the film. This model is shown in Fig. B-lo A parabolic velocity profile in the film is probably a'better approximation to the actual profile. This provides a second model, Model II. The physical surface used for obtaining the experimental data was a disk, so a disk is used for a flat plate in Models III and IV. Flow around the disk would be axisymmetricalo Models III and IV utilize a disk with uniform and parabolic velocity profiles in the film, respectively. 191

192 / Solid-Vapor Interface p=O Y Vapor Film V V constan Y x P2 L1 \1 Liquid-Vapor Interface Flat Plate - Model I F Solid-Vapor Interface V=Vmx(l- y y Vmaxi max Y2 Y2 Y1 P2 Liquid-Vapor Interface Disk - Model IV Fig. B-1. Plate and disk configurations.

193 The disk with the parabolic velocity profile in the film, Model IV, should most nearly approach the actual situation. This model is shown in Fig. B-1. It was assumed that the process was one which could'be treated as a steady-state phenomenon. The vapor was considered to be an inviscid fluid. It was assumed there was no flow in the z-direction (plate) or G-direction (disk), that dp/dy = 0 in the vapor, that d.p/dx = constant, and that Y1 >> 61. The assumption of no flow in one direction limits the number of dimensions which must be treated in the problem. The assumption dp/dy = 0 in the vapor eliminates consideration of flow.in the vapor normal to the plate. The assumption dp/dx = constant amounts to assuming that the vapor film thickness varies linearly with x. The assumption yL >> 61 permits the film to be approximated'by a film of uniform thickness in certain aspects of the calculations. With these assumptions, the momentum equation is =F = pV.(Vj)dA (B-l) A where E F= - pidA (B-2) A For the plate, the significant direction of the motion is along the x-axis. Writing the momentum equation for this component = pVx(Vn)d (By5) A and noting that P1 and P2 may be expressed in the form ply ~-, it may be

194 shown that Pi g 22 (3.4) 2 P\k (B-~) XFx 2 Yi-Y2) pvx((-. )dA - PVy2V2 x (-5 ) A For a steady-state system, conservation of mass requires that the mass flowing into the system'be equal to the mass flowing out. For this system, where the mass flow of vapor in is the result of evaporation of the liquid, the mass flow in is a function of the heat transfer rate, the average enthalpy difference between liquid and vapor, and the heat transfer area. Equating the mass flow in and. the mass flow out we may write =[ h(q/A). j = RPvY2lVx (B-6) from which it may be seen that Vxv = (q/A).L (_) hfgPvy2 Expressing the term (y2~-Yy) as (yl-y2)(yl+y2) and noting that (Y1-Y2) = 6 and, since Yl >> b1, Yl y Y2, and (Y1+y2) = 2yl, we may rewrite (y2l-ya) as 2y6l1. Substituting into Eqs. (B-3) through (B-7), the expression =f1 = ( /A ~9 P * - (B-8) hfg pIpvg is obtained which expresses the film thickness and thickness variation in terms of measurable parameters for Model I.

195 If a parabolic velocity profile is assumed, Model II, in the form V = Vma 4 (y2-y) (B-9) Eqs. (B-5) through (B-8) become, respectively 6 pV(V~ n)dA = Y2V max 1 (B-10) A 15 pv- max go... = A —. = 2vY2i1Vmax (B-ll) hfg J 3. (q/A)L Vmax = (B-12) hfgPvY2 - 2;1y2= 6 (q A)-.L 1 (B-13) 5 L hfg Pvp g For the axisymmetric case with a uniform velocity profile, Model III, Eqs. (B-4) through (B-8) become, respectively o= PQ ~RK-o [ y2 2 1 R(yj-y2)(y+2y2) (B-14) ZFx = Pg 9 Ryl-y22 y (y-2B-14) go L ~ 3 iR2+(y3-y2)2 pV( n)dA = PVY2VXvR 1 (B-15) A 90 = /) hR Pv vVrv. Ry2 (B-16) Vr (q/A)R (B7) v hfgPvY2 VXv = Vrv cos (B-18)

196 2 1 Yl Yl = (q/A) R 1 (B-l9) 3 hfg P jPvg When Eq. (B-9) is used for the velocity profile, Model IV, the axisymmetric Eqs. (B-15), (B-16), (B-17), and (B-19) become pVx( n)dA = PV2RY2 (B-20) 15 v may go A h = < = PvVmeax 3 Ry2 (B-21) (q/)R =Pvmax 3Ry Vmax = ( q/A)R (B-22) hfgPVY2 51Y: blYl =10 L J Pv (B-25) Solutions of Eqs. (B-8), (B-13), (B-19), and (B-23) using measured or estimated physical parameters permits a determination of the relationship'between Y1 and 61. If Y1 is measured, an estimate for,1 may'be made. The explicit determination of yi, and hence 61, would result from the simultaneous solution with the energy equation.

APPENDIX C THE EFFECT OF AIR DRAG ON MEASURED (a/g) DURING FREE FALL The drag force acting on a body moving through the air is given as57 FD = 1 pV2 CDA (C-l) 2 where p = density of air V = velocity of body relative to the air CD = drag coefficient A = area of body normal to air flow The velocity of the test packages at the instant of impact is 45 feet per second. Using a reference length of 1 foot, the Reynold's Number varies from about 10 soon after the package is released to 3 x 105 at impact. In this range, the CD of the first test package should be approximately that of a flat plate in three-dimensional flows ioe., 117i8 The CD Of the second test package should'be approximately that of a rounded head cylinder in three-dimensional flow, ie., 0.2.58 The free fall (q/A) vs. ATsat data are evaluated during the period from 0.7 to 1.4 seconds after release. The transitory effects caused'by the release have disappeared by 0.7 second9 and impact occurs at 14 seconds. Using the measured frontal areas of the packages (1l55 feet2 for the first package and 1.07 feet2 for the second package) and the velocities cor197

198 responding to the above times (22.5 feet per second at 0.7 second, 45.0 feet per second at 1.4 seconds) the forces acting on the packages may be calculated using Eq. (C-1). They are FD(first package, 0.7 second) = 1.07 lbf FD(first package, 1.4 seconds) = 4.28 lbf FD(second package, 0.7 second) = 0.124 lbf FD(second package, 1.14 seconds) = 0.465 lbf The force due to air drag on the second test package is approximately 10% of the force due to air drag on the first test package. Using the relationship (a)free fall=_ FDfree fall (C-2) g ree fall and the above values of FD, noting that the weight of the first package is 120 pounds and the weight of the second package is 135 pounds, (a/g) (free fall, first package9 0 7 second) = 0.0090 (a/g) (free fall, first package, 1,4 seconds) = 0.0357 (a/g) (free fall, second package, 0,7 second) = 0o00093 (a/g) (free fall, second package, 104 seconds) = 0.00374 For the first test package, the effective (a/g) during free fall will range from 0.01 to 0.035 because of variation in air drag. Any effects due to guide wire drag would further increase the value of (a/g)o Because (q/A) and ATsat are evaluated prior to package impact, (a/g) increases due to air drag should be in the range 0.01 < (a/g) < 0~03.

199 For the second test package, the effective (a/g) during free fall for the outer package will range from 0.001 to 0.0037. The inner package should not feel any effect of the air drag on the outer package, and so should experience a lower (a/g) than the outer package.

APPENDIX D EVALUATION OF THE LUMPED ANALYSIS APPROXIMATION When a spherical solid at a high temperature is immersed in a liquid at a lower temperature, unsteady conduction takes place in the sphere. The reference parameter describing the internal differences in temperature for this problem is the Biot Number, Bi = = R (D-l) ks which can be interpreted as the ratio of internal to external thermal resistances. When the Biot Number is less than approximately 0o1, the solid may be treated as a lumped system with a fair degree of precision. When the Biot Number is greater than 0.1, the solid must be treated as a distributed system, and analytical solutions are generally available only for limited types of boundary conditions. The use of numerical solutions is required for general cases. A calculation of the Biot Number for the 1-inch diameter sphere in the film-boiling region, using values of h from measurements assuming lumped conditions, gives values of less than 0.02 for all combinations of pressure and subcooling investigated. Carslaw and Jaeger59 have presented a solution to evaluate the temperature at any point in a sphere as a function of time after a heat flux, (q/A), has suddenly been imposed. They give 200

201 3((q/A)t (q/A)(5r2-3R2) T(t r) - To + PsdCpaR 10k sdR Psd Psd sd 2(q/A)R2 -;sin(r1. e -sdnt/R (D ksdr n=l an sinkn where T(tr) = temperature at time t and radius r To = temperature at time zero R = radius of sphere 0< r <R -a = thermal diffusivity Xnn = 1,2,.., are the positive roots of tan k = & Equation (D-2) was evaluated for r=0O and r = R = 1/2 inch with (q/A) = 104 Btu/hr-ft2, Cpd = 0.08 Btu/lbm-OF, psd = 558 lbm/ft3, ksd = 224 Btu/ hr-ft-~F, and t = 1 second. The heat flux used might be considered an upper li.mit for film boiling under the conditions present., A difference of 0.93~F was predicted between the temperature at the center and the temperature at the surface of the sphere. In view of the small Biot Number with f:ilm boiling, it appears reasonable to expect that the rates of change of center and surface temperature will not differ significantly. The error in calculating (q/A) due to assuming a uniform temperature in the sphere would -be due to this difference, and to variations in Cp with T within the sphere. This is less than 0.05%, which may'be neglected. In the nucleate and transition'boiling regions, values of the B:iot Num'ber are of the order of magnitude of one, indi.cating that computation of

202 the surface heat flux will require evaluation of the distributed nature of temperatures in the sphere. This is accomplished using finite difference procedures, with the measured surface temperatures as inputs. The flow sheet for the computer program is shown in Fig. D-l, and the program listing is shown in Fig. D-2. The computer language used is MAD. The program takes the raw time vs. surface temperature data and fits a fifth order polynomial to the first five points using the method of least mean squares. It divides the sphere into ten concentric shells about a spherical core and calculates the heat flux into the sphere in terms of the enthalpy change of each shell evaluated at intervals of 0.00010 second between the second and fourth points (see Fig. D-3). The heat flux, surface shell temperature, next shell temperature, and spherical core temperature, as well as ATsat and some other computational information, are printed out for the third point. The first data point is then dropped9 the sixth data point is added to'become the new fifth point., a new polynomial is fit to the data points, and the process is repeated. After all of the data points have been handled in this way the results are printed and plotted as shown in Chapter V.

203 Read Print Identification dentificatio I ~~~~~~~~~~IlI I1 + JC JC (N+1)12I>"' l > (N4-(N/2)-2) F _ T DD 1. DD > N X(DD) = DD +DD+1 tF DL F se rd Itlcmue prga Fig. D-1. Flow sheet for digital computer program.

204 (SD2/N)<O.O DE T SE = TP f O I' DE > N: C2 = -~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ C2 DE DE+l G1 - I1-2 C3 =... I G1 t G1 + 1 K- I1-l / < 1 > I + 2 G1I2 I 1 1+ K2 I2+1 > 2 JF +~ JF JF+1 Fig. D-1 (Continued)

205 L +- 1 ACP...' L> PK F 1 > 3 T or L + L+ L > 1 IF I S 1 IT I S 1 TIME... Fi. D- 1 ( Continued)...> F T(S)=... StS+ S t+ s = 1~L~CTNO=... TN)=.. F T~ S < SM )-~DRR=... 2()... IM..<0.00 F I~~~~~~~~Y2()=... ~IME. < 0)<. O0q Y2( TIME... <0. — im Y2('=... TME.. <0.001 Y2()=... TME.. <0.00 Fig. D-1 (Continued)

206 I arI JZ 1 JZ S > SM YZ (JZ)= -* SI igt Results 1 = r RTA...ults QAB(): ("i Fig. D-1 (Continued)

207 Print Print Print I d.Plot of Plot of Plot of - ~ Temperature Log (q/A) vs. (q/A) vs. vs. Time Log AT Time Print Results AT (q/A), sat' I Time Fig. D- Print [IV ~ Intermediate SD2 -SD2 Calculations Fig. D-1 (Concluded)

$COMPILE MAD, EXECUTE, DUMP, PRINT OBJECT, PUNCH OBJECT 053478 04/18/67 12:02 41.7 AM MAD (06 JAN 1967 VERSION) PROGRAM LISTING. START CONTINUE *001 INTEGER RUN,I1 112,K,LR, SSM,NNI N3,N4,J8,J9,J12,J14,Jl5 *002 INTEGER J16,GlJAJCJF *003 INTEGER DDDEIIC3,C4 *004 INTEGER TPJZ *005 DIMENSION X(25 ),Y(25),XL(1 00bYl(2500,YlDIM),X2(100),Y2(121,Y2DIM) *006 DIMENSION X3(100),Y3(1211 Y3DIM),T(100),TN(100),TA(100),RUN(12) *007 DIMENSION CTEM(52),CCP(52),GRAPH(867),EX(100),WY(100),S'TDX(.120) *008 DIMENSION STDY(120),STAX(120),STAY(120),OATAX(100),OATAY(100) *009 DIMENSION DATX(100),DATY(100),TIM(100),TEM(100),QAB(100),DTT(100) *010 VECTOR VALUES YIDIM = 2,1,50 *011 VECTOR VALUES Y2DIM = 2,1,11 *012 VECTOR VALUES Y3DIM = 2,1,11 *013 VECTOR VALUES OUT. = $IHI, 12C6*$ *014 VECTOR VALUES OUT1=$LHO,12C6*$ *015 VECTOR VALUES IN=$12C6*$ *016 VECTOR VALUES ABS=$1H0O,30,24HLOG (TS-TSAT), DEGREES F*$ *017 V.ECTOR VALUES LFO=$ TEMPERATURE, DEG F $ *018 VECTOR VALUES ABS1$lHO,550,22HRELATIVE TIME, SECONDS*$ *019 VECTOR VALUES ORD=$ LOG Q/A, BTU/HR-FT2 *$ *020 VECTOR VALUES QA=$ Q/A, BTU/HR-FT2 *$ *021 VECTOR VALUES EX(1)= 0.0,0.301, *022 1 0.477,0.602,0.699,0.778,0.845,0.903,0.954,1.0, *022 2 1.301,1.477, *022 3 1.602,1.699,1.778,1.845,1.903,1.954',2.0, *022 4 2.301,2.477, *022 0 5 2.602,2.6 99,2.778,2.845,2.903,2.954,3.0 *022 VECTOR VALUES WY(l)= 3.0,3.301, *023 1 3.477,3.602,3.699,3.778,3.845,3.903,3.954,4.0, *023 2 4.301,4.477, *023 3 4.602,F4.699,4.778,4.845,4.903,4.954,5.0 *023 VECTOR VALUES STDX(1)= 5.896.0,6.2,,6.4,6.6,6.8,7.0,7.2,7.6,8.0,8.5, *024 I 9.0,9.5,10.0,11.,12.,13.,14.,15.,16.,17.,18.,19.,20.,21., *024 1 22.923.,24.,25.,26.,27.,28.,29., 30.,31.,32.,33.,34.,35.,36., *024 I 37.,38.,39.,140.,42.,44.,46.,48.,50.,52.954.,56.958.960.962., *024 1 64.,66.,68.,70.,72.,76.,80.,85.990.,95.9100.,110.,120., *024 1 130.,140.,150.,160.,170.,180.,190.,200.,210.,220.,230., *024 1 240.,250.9260.,270.,280.,290.,300.,310., 320.,330.,340.,350., *024 1 360. *024 VECTOR VALUES STDY(1)= 1350.,1500.,1700.91900.,2100.,2300.,2550.,2800., *025 1 3400.,4000.,4900.,6000.,7200.,8500.,11900.,15700.,20900., *025 1 26600.,33700.,39200.,43000.,44750.,46000.,46250.,46250., *025 1 45800.,45000.,44000.,42200.,40500.,38750.,36500.,34000., *025 1 30700.,27500.,24300.,21700.,19700.,15000.,12000.,9700.,7500., *025 1 6000.,4550.,2650.,1725.,1680.,1690., 1725., 1760.,1805.,1845. *025 1 1890.,1920.91960.,2000.,2040.,2080.,2115.,2150.,2235.,2300., *025 1 2400.,2490.,2585.,2675.,2860.,3020.,3200.,3380.,3550.,3710., * 025 1 3900.,4050.,4225.,4400.,4575.,4'750.,4900.,5050.,5225.,5400., *025 I 5575.,5750.,5900.,6025.,6200.,6400.,6550.,6700.,6850.97000. *025 VECTOR VALUES CTEM(1)= -360.,-350.,-340.,-330.,-320.,-310.,-300.,-290.t *026 1 -280.,-270.,-260,-250,-240.,230.9- 22O.,21O.,200.,l9., *026 I -180.,-170.,-160.,-150., 140.,-130.1,-120.,-110.,-100.,-90., *026 1 -80.,-70.,-60.,-50.,-40.,-30.-20. -10.,0.0,10.,20.,30.,40., Fig. D-2. Digital computer program listing.

% 50.,60.,70.,80.,90.,100.,110.,120.,130.,140. *026 YECTOR VALUES CCP(1)= 0.0305, *027 1.0359,. 0407,.045,.0489,.0524,.0557,. 0589, *027 1.0-618,.0642,.0662,.0681,.0699,.0716,.0732,.0747,.076,.0773, *027 1.0'784,. 0794,.0804,.081 3,.0822,. 083 1,.0839,.0847,.0854,.086, *027 1.0866,.0872,.0877,.0882,.0886,.0891,.0895,.0899,.0903,.09065, *027 1.091, 0912.09125,.09155,.0918,.09205,.0923,.0925,.0927,.09285, *027 1.093,. 09315,.09325,.0934 *027 MPY= 2.302585 *028 N1=92 *029J14=28 *030 J15=19. *031 READ FORMAT IN, RUN( 1)...RUN(12 *032 PRINT FORMAT OUT, RUNI1)...RUN(12) *033 READ DATA *034 PRINT RESULTS N4,N,RO,VOA,DR,IC,DS,SM,RZTSAT,TIM(l1... TIM(N4), *035 1 TEM 1...TEM(N4) *035 WHENEVER N.L. 5, TRANSFER TO START *036 JC=(N+1)/2 *037 THROUGH LOOPB,FOR I1=JC,1,11.G.(N4-(N/2)-2) *038 THROUGH LU1, FOR DD=1,I,DD).G.N *039 01 Y(DD)=(TEMDD+ I 1-JC+2)-TEM(DD+I 1-JC ) / ( TIM(DD+ I 1-JC+2) *040 02 1 -TIM(DD+I1-JC)) *040 LU1 X( DD)=T IM(DD+I 1-JC+1) *041 02 TP=O *042 01 HRZ SX=O.0 *043 01 SX2 = 0.0 *044 01 SX3 = 0.0 *045 01 SX4 = 0.0 *046 01 SX5 = 0.0 *047 01 P SX6 = 0.0 *048 01 0 SY = 0.0 *049 01') SXY = 0.0 *050 01 SX2Y= 0.0 *051 01 SX3Y= 0.0 *052 01 SY2 = 0.0 *053 01 THROUGH LPA, FOR I = 1, 1, I.G. N *054 01 SX = SX + X(I) *055 02 SX2 = SX2 + X(I).P. 2 *056 02 SX3 = SX3' + X(I).P. 3 *057 02 SX4 = SX4 + X(I).P. 4 *058 02 SX5 = SX5 + X(I).P. 5 *059 02 SX6 = SX6 + X(I).P. 6 *060 02 SY = SY + Y(I) *061 02 SXY = SXY + Y(I)*X(I) *062 02 SX2Y = SX2Y + YII)*X(I)*X(I) *063 02 SX3Y = SX3Y + Y(I)*X(I).P. 3 *064 02 LPA SY2 = SY2 + Y(I)*Y(I) *065 02 V1= N/(N*SX2 -SX*SX) *066 01 V2=( SX*SX3/N)-SX4 *067 01 V5=SX2/N *068 01 V6= SX* S X2-N*SX3 *069 V7=SX2*SX3/N-SX5 *070 01 V9=SXY-SX*SY/N *071 01 Vl=1/(SX4-(SX2*SX2 /N) -((V6/N)*(V6/N)*Vl)) *072 01 V13=SX2Y-V5*SY+V 1V9*V6/N *073 01 V15=Vl*( V6/N)*V2+V7 *074 01 V16=SX3Y- SX3*SY/N )-SX4*V*V9-SX5*Vll*V13 *075 V17=SX2*SX3/N-SX4*VI*V6/N *076 01 V18=SX3*SX3/N-SX4*Vl *V2-'SX5*V1*V15 *077 01 Fig. D-2 (Continued)

V19=SX*SX3/N *078 01 A3=(V16+V1*V9*V19+( V17+Vl*V6*V19/N) *V 1V3) /(SX6-V18-V1*V2* 079 01 1 V19-V11*V15*V1 7+V1*V6*V19/N)) *079 A2=V11. (V13+V15*A3) *080 01 AI=V1* (V9+ ( V6/N) *A2+V2*A3 ) 081 01 AO=( 1./N)*(SY-A1*SX-A2*SX2-A3*SX3) *082 01 SD2=SY2-( AO*SY+A 1*SXY+A2*SX2Y+A3*SX3Y) *083 01 WHENEVER (SD2/N).L.O.0, TRANSFER TO ERRRT *084 01 HRA WHENEVER TP.NE.0, TRANSFER TO HRX *085 01 SE=SQRT. ( SD2/N) *086 01 C2=0.0 *087 01 THROUGH. LU2, FOR DE=,1,DE.G.(N+1) *088 01 LU2 C2=C2+(TEM(DE+Il1-JC+1)+TEM(DE+I11-JC))*(TIM(DE+11-JC+1 *089 02 1 -TIM(DE+I1-JC) )/2. *089 C3=I 1-JC+N+2 *090 01 C4=11 -JC+1 *091 01 C1=(C2-(AO/2.)*(TIM(C3).P.2)-(TIM(C4).P.2) ) *092 01 I -(Al/ 6.)*( TIM(C3).P.3)-(TIM(C4).P.3)) *092 1 -(A2/12.)*( (TIM(C3).P.4)-(TIM(C4).P.4 )) *092 1 -(A3/20.)*((TIM(C3).P.5)-(TIM(C4).P.5)) )/ *092 1 (TIM(C3)-TIM(C4)) *092 BO=AO *093 01 B1=AL *094 01 B2=A2 *095 01 83=A3 *096 O0 THROUGH LOOPC, FOR G=( I1-2),GI.G. ( I 1+2) *097 01 X1(G1 )=X(G-I1+3) *098 02 LOOPC Y1 (G1,( I1-2 )=AO*XI G1) +A*XI(G1)*X(G1)/2. *099 02 1 +A2*Xl(GL).P.3/3.+A3*Xl(G1).P.4/4.+C1 *099 THROUGH LOOPD, FOR K=11-l,1,K.G.(I1+2) *100 01 THROUGH LOOPD,FOR 12=K,1,12.G.(I1+2) *101 02 LOOPD Y( I 2,K)=(YI(I2,K-1)-Y1( I2-1,K-1) )/( X( 12)-X1( I2-K+I 1-2)) *102 03 THROUGH LPR, FOR JF=l,,JF.GE.52 *103 01 0 LPR WHENEVER (Yl(l,(11-2) )-CTEM(JF)).L.O.G,TRANSFER T(] HR3 *104 02 PRINT RESULTS JF,CTEM(JF),AO,AI,A2,A3,XL(I1-2)...(I1..+2), *105 01 I Yl (I1-2), (I1-23))...YI((11+2), (I1-2)) *105 TRANSFER TO START *106 01 HR3 ACP=CCP(JF-1)+((CCP(JF)-CCP(JF-1))*(Yl(11,(I1-2))-CTEM(JF-1)) *107 01 1 /10.0) *107 CQ=RU*DR*DR*3600. / ( TC*DS) *108 01 MM=ACP*CQ *109 01 PK=( X1( l+1)-X1(I1-1))/DS *110 01 THROUGH LOOPB, FOR L=1,I,L.G.PK *111 01 WHENEVER I1.G.3.OR.L.G.1,TRANSFE TO PSI 112 02 THROUGH LOOPE, FOR S=l,i,S.G.SM *113 02 LOOPE T(S)=Y12, 1) *114 03 PSI TIME=X1(11-1)+L*DS *115 02 T(1)=BO*TIME+B1*TIME.P.2/2.+B2*TIME.P.3/3.+B3*TIME.P.4/4.+C1 *116 02 THROUGH LOOPG, FOR S=1,1,S.G.SM *117 0'2 WHENEVER S.E.1 *118 03 TN(1)=T(1) *119 01 03 OR WHENEVER S.L. SM *120 01 03 DRR=DR/ ( RZ-( S- 1) *DR) 121 01 03 TN(S)=(T(S+1)*(.-DRR) +T(S-I)*(1.+DRR) +(MM-2.)*T(S) )/MM *122 01 03 OTHERWISE *123 01 03 TN(S)=(6.*T(S-1)+(MM-6.)*T(S))/MM *124 01 03 END OF CONDITIONAL *125 01 03 WHENEVER.AS.(TIME-( X 1 (I1)-2.*DS).L..00010 * 1'26 03 Y2(S,)=TN( S) *127 01 03 X2( I )=TIME *128 01 03 Fig. D-2 (Continued)

R=1 *129 01 03 OR WHENEVER.ABS.(TIME-IXIl(I1)-DS)).L.O.00010 *130 01 03 Y2(S,2)=TN( S) *131 01 03 X2 2)=TIME *132 01 03 R=2 *133 01 03 OR WHENEVER.ABS.(TIME-X II1)).L.O.00010 *134 01 03 Y2( S,3) =TN( S) *135 01 03 X2( 3)=TIME *136 01 03 R=3 *137 01 03 OR WHENEVER.ABS.(TIME-(Xl{(I1)+OS)).L.O.00010 *138 01 03 Y2(S,4)=TN(S) *139 01 03 X2(4)=TIME *140 01 03 R=4 *141 01 03 OR WHENEVER.ABS.(TIME-(XlI(1l)+2.*DS)).L.O.00010 *142 01 03 Y2(S,5)=TN( S) *143 01 03 X2(5)=TIME *144 01 03 R=5 *145 01 03 TOD=Y2( 1,3)-TSAT *146 01 03 LOOPG END OF CONDITIONAL *147 01 03 THROUGH LOUPH,FOR S=1,1,S.G.SM *148 02 LOOPH T(S)=TN(S) *149 03 WHENEVER.ABS.(TIME-(Xl(Il)+2.*DS) ).L.O.00010 *150 02 THROUGH LOOPL,FOR R=1,1,R.G.5 *151 01 02 SUM=( ( SM-1.).P.2*Y2( 1, R))/2. *152 01 03 THROUGH LOOPJ, FOR S=2,1,S.F.SM *153 01 03 LOOPJ SUM=SUM+( (SM-S).P.2)*Y2(SR) *154 01 04 TA(R)=3.*SUM/(lSM-l. ).P.3) *155 01 03 X3(R)=X2(R) *156 01 03 LOOPL Y3(R,I)=TA(R) *157 01 03 THROUGH LPZ, FOR JZ=l,1, JZ.G.5 *158 01 02 X(JZ)=X3(JZ)-TIME+2.*i)S *159 01 03 LPZ Y(JZ)=TA(JZ) *160 01 03 H TP=1 *161 01 02 - TRANSFER TO HRZ *162 01 02 HRX TG=AI+2.*A2*X( 3}+3.*A3*X(3)*X(3) *163 01 02 PRINT RESULTS X2(l),X2(2),X2(3),X2(4),X2(5),TIME,TG,X(3) *164 01 02 Q=RO*ACP*TG*VUA*3600. *165 01 02 PRINT RESULTS X2(3),Y2(1,3),Y2(2,3),Y2(11,3),ACP,Q,TD,SE *166 01 02 WHENEVER Q.G. 100000.0, TRANSFER TO LP2 *167 01 02 QAB ( I 1-JC+1)=.ABS. (Q) *168 01 02 OTT ( I 1-JC+1) =TD *169 01 02 DATAX(t I 1-JC+1)=.ABS.(TD) *170 01 02 DATAY( I 1-JC+1)=QAB( I 1-JC+l ) *171 01 02 END OF CONDITIONAL *172 01 02 LOOPB CONTINUE *173 02 LP3 N3=I 1-JC *174 PRINT COMMENT $1$ *175 EXECUTE SETPLT. ( 1,TIM(I1),TEM(1),N4,$*$,38,LFO) *176 PRINT FORMAT ABS1 *177 PRINT FORMAT OUT1, RUN(1)...RUN(12).*178 THROUGH LOK,FOR J9=1, 1,J9.G.N1 *17c2 STAX(J9)= ELOG.(STDX( J9} ))/MPY *180 01 LPK STAY(J9)= ELOG.(STOY(J9)) }/MPY *181 01 THROUGH LPO, FOR J16=1.1,J16.G.N3 *182 DATX(J16) =ELOG.(DATAX(J16) 3/MPY *183 01 LPO DATYIJ16) =ELOG.(DATAY(J16) )/MPY *184 01 EXECUTE PLOTI. (0,2,25,3,33) *185 EXECUTE PLOT2.(GRAPH,3.,.0,5.,3.) *186 THROUGH LPJtFOR J12=1, 1,J12.G.J14.*187 EXECUTE PLOT3.($+$,EX(J12),3.0,1) *188 01 Fig. D-2 (Continued)

EXECUTE PLOT3.(S+$,tEX(J12),4.Ol) *189 01 LPJ EXECUTE PLOT3.I$+$,EX(J12),5.O,1) *1906 THROUGH LPNFOR J8=ltltJ8.G.J15 *191 EXECUTE PLOT3.($+$,O.0,WY(J8),1) *192 01 EXECUTE PtOT3.($+$,1.OWY(J8)91) *193 01 EXECUTE PLOT3.($+$,2.02WY(J8),1) *194 01 LPN. EXECUTE PLOT3.($+$,3.0O,WY(J8)1,) *195 01 EXECUTE PLOT3.(S.$iSTAX(l),STAY(1),Nl) *196 EXECUTE PLOT3oC$*$,DATX(l),DATY(1,,N3) *197 PRINT COMMENT $15 *1g8 EXECUTE PLOT4.(32,ORD) *199 PRINT FORMAT ABS *200 PRINT FORMAT OUT1, RUN(1)...RUN(12) *201 PRINT COMMENT $1$ *202 EXECUTE SETPLT. (lTIM(4)QAB(l), (N4-6),$*$932QA) *203 PRINT FORMAT ABSi *204 PRINT FORMAT OUTL1 RUN(1)...RUN(12) *205 PRINT FORMAT OUT, RUN(1)...RUN(12) *206 PRINT RESULTS DTT(1)...DTT(N31,QAB(1)...QAB(N33, *207 OATAX(1)...OATAX(N3), TIM(l)...TIM(N4) *207 TRANSFER TO START *208 ERRRT PRINT COMMET 5- NEGATIVE SQUARE ROOT - ERROR IN STD DEV S *209 PRINT RESULTS NAOAlA2,A3,502,(SD2/N) *210`-S02=-502 *211 TRANSFER TO HRA *212 LP2' N3=I1-JC+1 *213 TRANSFER TO LP3 *214 END OF PROGRAM *215 IFC Fig. D-2 (Conclude&) I')

Heat Flux Calculations Use Central Computed Points (I) 1 2 3 4 5 6 7 8 Data Index No. Computational Steps > i Illlllllllllllllllllllllll lllllllll? O o.ooo(00010yp) Computational_ a) | l | Interval j 0)O Polynomial Interval Time, Sec. b Fig. D-3. Computational procedure for digital computer program.

APPENDIX E ANALYSIS OF THE TEST PACKAGE-STEEL CABLE-COUNTERWEIGHT SYSTEM A sketch of the test package —steel cable-counterweight (p-c-c) system is shown in Fig. E-lo The cable is assumed to pass over two frictionless pulleys and to be weightless and inextensible. Writing the equations of motion for the test package and the counterweight. ZFy = may (E-l) or Fc - meg = mcas (E-2) mpg - Fc = mpas (E-3) for which the solution is as mp-mc (E-4) g mp+mc Fc = m g + (E-5) w:here ZFy = sum of the forces in the y-direc'ion m = mass mc = mass of counterweight mp = mass of test package ay = acceleration in y-direction

215 -inch Diameter Steel Cable Pulleys m m Counterweight C P Test Package F F Iy sI cs m Fig.-1. ketcandfrc bodydiagramoftest pa -P Fig. E-1. Sketch and free-body diagram of test package-steel cable-counterweight system.

216 as = acceleration of p-c-c system g = acceleration due to gravity Fc = tension in cable The effective body force acting on a body which is moving with the test package is FB = mBaB (E-6) where FB = effective body force acting on body moving with test package mB = mass of body moving with test package aB = net acceleration of body moving with test package The net acceleration aB = g - as or =-:1 _ -s (E-7) g g When mc = O, i.e., the test package is in free fall, (as/g) = 1, Fc = 0, and (aB/g) = O. This indicates that a body moving with the test package in free fall is subjected to the same forces which it would be subjected to in a, zero-gravity environment. When mcg = 11 pounds and mpg = 120 pounds, (as/g) = 0.835 Fc = 20o2 l'bf, and (aB/g) = 0017. This indicates that a body moving with the test package in counterweighted drop, assuming the weights given above, is su'bjected to the same forces which it would be subjected to in an environment possessing

217 a gravitational field 17% as strong as that on the earth. The actual p-c-c system differs from the idealized system described above. The values of (aB/g) were measured using an accelerometer mounted on the test package. The measured values of (aB/g) were approximately 15% higher than those calculated using Eq. (E-7) for counterweighted drop. This difference is attributed primarily to friction losses in the pulleys and'bending losses in the cable, with a small effect due to guide wire drag, which increase the effect:ive mass of the counterweight, and thus (aB/g)o The assumption that the steel cable is inextensible is not a good assumption for this system. The measured spring constant was 308 lbf/in. The dynamic system may'be represented as shown in Fig. E-2, with mc and mp each resting on a frictionless surface and connected by a spring with spring constant kc and FBp and FBc representing the gravity forces acting on the test package and counterweight, respectively. An initial deflection of the spring is considered, depending on whether the system is:initially restrained at the counterweight or test package, A or B in Fig. E-2. The equations of motion may be written as mc d2Xc - kc(xp-xc) + FBc = 0 (E-8) dt2 mp + kc(p-xc)- FBp = O(E-9) dt2 When the system is initially restrained at the counterweight, A in Fig. E-2. the test package accelerati.on iss

218 F kc BC 0 _A xp B Fig. E-2. The test package-steel —cable counterweight system as an idealized mass-spring-mass system.

.219 d2X = mp- mc (1-cos ot)g (E-1o) dt2 mp+mc where w is the natural frequency of the system. The solutions for X are k (mp+m) (E-ll) - C=CMP 0 (E-lo) mpmc Using values of kc = 308 lbf/inch, mcg = 11 lbf, and mpg = 120 lbf in Eq. (E-ll), w = 108.8 radians/sec, and the predicted oscillation frequency, f, for the system is 17.3 Hertz. This solution assumes no damping in the system, and therefore gives an upper limit for f. The general solution of Eqso (E-8) and (E-9) with the appropriate initial conditions, given as Eq. (E-10), showsthat the effective body force present on the test package will oscillate about the steady value. Evaluating Eq. (E-10) using the values given above, the test package acceleration is given as dp = 0.83(1-cos 108.8t)g (E-12) dt2 which predicts that an accelerometer mounted on the test package would show an average value of (1-0.83)g = 0.17g, but with a superimposed oscillation of amplitude 0.83g. When the system is initially restrained at the package, B in Fig. E-2, the test package acceleration is d = mp-m ct)g (E-13) dt2 mp+mc (1 + pcos t)g (E1 Using the values given previously, the test package acceleration is given as

220 d2Xp = 0.83(1+0.09 cos 108.8t)g (E-14) dt2 which predicts that an accelerometer mounted on the test package would show an average value of (1-0.83)g = 0.17g, but with a superimposed oscillation of amplitude 0.076g. Measurements of (aB/g) as a function of time using the values of kc, mcg, and mpg given previously were obtained and are shown in Fig. E-3. The chart labeled "counterweight released in basement" was obtained using the cable to support the test package (A in Fig. E-2)o The chart labeled "package released by burning wire" was obtained using the cable to support the counterweight (B in Fig. E-2). The initial amplitude of the oscillations in (aB/g) are much larger for the case where the largest mass (the test package) was being supported. This amplitude decreases over the first several cyclesj indicating that damping is taking place. The oscillation frequ.ency is the same for both measurements, approximately 13 Hertz. If viscous damping is assumed, a value of the damping factor of 0.66 is indicated. The damping is probably not viscous, because a damping factor of o.66 indicates large damping, but relatively little damping is indicated on the traces. The appearance of the traces on Fig, E-3 indicates that several factors probably influence the oscillation behavior of the p-c-c system. The pulleys over which the cable passes, internal damping in the cable, the fact that the cable cannot sustain compressive forces and the possibility of some internal oscillation within the test package itself, are probably among the most significant.

~~Cli E ~.~, I.. 1'.................... -7~~~~~~~~~~~ ~ i.............Ic..........;,.......rl... 1.1~......... * ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~........; II~~~~~~~~~~~~~~~~~~~~ ~r:" t ~(L~+ -r -t —~ —~~~~~~~~~~~~~~~......................t cl~-; - t ~r -~ -s- ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~...?Ifil I.1 ~ t~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ [[rill If if -...... f —t- II: iI 1 I I- I.ii [it fill1\. ii t: ~+ c~!t:~ A 1i Lf-, -i~ I AL I. IL i il ls ~' r Itr: ~ t ~~1: ~1~~ —; ~:''t ~: W III-If UPI I Al Ir I I~~~~~~~~~~~~~~ I V ~ IA 1 1 I L. I I I ~-t - -, I f~ ~ ~ to II I v. I IA I f~t It I 1 4.t. t T f-I IC ij i Li I I I I~ ~ ~ ~ ~ ~ ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~tfirtti tii~t~tr - ~1tt ll: r_ Li: Fig E-. Acelromte reord of(aBg)

222 With these limitations in mind, it is interesting to compare the traces of Fig. E-3 with the predictions of Eqs. (E-12) and (E-14)) When the counterweight is released, the initial large irregular oscillations are probably caused by the counterweight trying to compress the cable (with resultant cable buckling) then dropping'back down to again put the cable in tension. The +0.83g oscillation predicted is not sustained, although it may be present in the first cycle.'When the package is released, a more regular trace is obtained. Cable buckling is probably not a problem for this case. The maximum amplitude of the acceleration var:.iation is less than 1~:O.lg, which is approximately as predicted by Eq. (E-14),) A beat in the oscillation amplitude may be seen, but there is no obvious cause for this.

BIBLIOGRAPHY 1. McAdams, W. H. Heat Transmission, 3rd edition, McGraw-Hill Book Co., New'York, 1954. 2. Kreith, F. Principles of Heat Transfer, 2nd edition, International Textbook Co., Scranton, Pa., 1965. 3. Berenson, P. J. "Film Boiling Heat Transfer from a Horizontal Surface," Trans. ASME Journal of Heat Transfer, Series C, 83, 351-'358 (1961). 4. Zuber, N. "Hydrodynamic Aspects of Boiling Heat Transfer," Atomic Energy Commission Report No. AECU-4439, Physics and Mathematics, June 1959. 5. Zuber, N. "On the Stability of Boiling Heat Transfer," ASME 57-HT-4. 6. Adelberg, M. "Boilling, Condensation and Convection in a Gravitational Field, " Paper presented at the 55th National Meeting of the A.I.Ch.E, Houston, Texas, Feb. 1965. 7. Clark, J. A. and Merte, H. "Boiling Heat Transfer to a Cryogenic Fluid in [Both Low and High Gravity Fields, " Paper presented at the XIth International Congress of Refrigeration, Munich, Germany, Aug.-Sept. [1963. 8. Keshock, E. G. and Siegel, R. "Forces Acting on Bubbles in'Nucleate'Boiling Under Normal and Reduced Gravity Conditions," NASA TN-D-2299, Aug.:1964. 9. Cochran, T. H. and Aydelott, J. C. "Effects of Subcooling and Gravity Level on Boiling in the Discrete Bubble Region," NASA Technical Note TN D-3449, Sept. 1966. 10. Beckman, W. A. and Merte, H. "A Photographic Study of Boiling in an Accelerating System, " Trans. ASME Journal of Heat Transfer, Series c, 87, 374-380 (1965). 11. Rohsenow, W. M. "A Method of Correlating Heat Transfer Data for Surface Boiling of Liquids," Trans. ASME, 74, 969-976 (1952). 12. Michenko, N. "On the Problem of Heat Transfer in Nucleate Boiling," Energomashinostroenie, No. 6, 17-21 (1960)o 223

224 BIBLIOGRAPHY (Continued) 13. Forster, H. K. and Zuber, N. "Growth of a Vapor Bubble in a Superheated Liquid," Journal of Applied Physics, 24, 474-478 (1954). 14. Engelberg-Forster, K. and Greif, R. "Heat Transfer to a Boiling Liquid —Mechanisms and Correlations," Trans. ASME Journal of Heat Transfer, Series C, 81, 43-53 (1959). 15. Frederking, T.H.K. "Gravity Effects on Interfacial Kinematics in Ordinary Boiling Systems," Paper presented at the Symposium on TwoPhase Flow, University of Exeter, Exeter, June 1965. 16. Merte, H., Jr. and Clark, J. A. "Pool Boiling in an Accelerating System," Trans. ASME Journal of Heat Transfer, Series C, 83, 233-242 (1961). 17. Costello, C. P. and Tuthill, W. E. "Effects of Acceleration on Nucleate Pool Boiling," Paper presented at the A.I.Ch.E.-I.M.I.Q. Joint Meeting, Mexico City, Mexico, June 1960. 18. Sherley, J. E. "Nucleate Boiling Heat Transfer Data for Liquid Hydrogen at Standard and Zero Gravity," Advances in Cryogenic Engineering, 8, Ed., K. D. Timmerhaus, Plenum Press, 495-500 (1963). 19. Merte, H. and Clark, J. A. "Boiling Heat Transfer With Cryogenic Fluids at Standard, Fractional, and Near-Zero Gravity," Trans. ASME Journal of Heat Transfer, Series C_ 86, 351-359 (1964). 20. Noyes, R. C. "An Experimental Study of Sodium Pool Boiling Heat Transfer," Trans. ASME Journal of Heat Transfer, Series C, 85, 125-.131 (1963). 21. Chang, Y. P. and Snyder, N. W. "Heat Transfer in Saturated Boiling," Chemical Engineering Progress Symposium Series, 56, No. 30, 1960. 22. Kutateladze, S. S. "A Hydrodynamic Theory of Changes in the Boiling Process Under Free Convection Conditions," Izv. Akad. Nauk. SSSR, Otd. Tekh. Nauk. No. 4, 529-536 (1951). 23. Moissis, R. and Berenson, P. J. "On the Hydrodynamic Transitions in Nucleate Boiling," Trans. ASME Journal of Heat Transfer, Series C, 85, 221-229 (1965). 24. Siegel, R. "Effects of Reduced Gravity on Heat Transfer," Proposed NASA Survey Article for Advances in Heat Transfer, March 1966.

225 BIBLIOGRAPHY (Continued) 25. Usiskin, C. M. and Siegel, R. "An Experimental Study of Boiling in Reduced and Zero Gravity Fields," Trans. ASME Journal of Heat Transfer, Series C, 83, 243-253 (1961). 26. Steinle, H. F. "An Experimental Study of the Transition from Nucleate to Fi:lm Boiling Under Zero-Gravity Conditions," Proceedings of the 1960 Heat Transfer and Fluid Mechanics Institute, Stanford University, 2084219, June 1960. 27. Bromley, L. A. "Heat Transfer in Stable Film Boiling," Chemical Engineeri. Progress, 46, 221-227 (1950). 28. Hamill, T. D. and Baumeister, K. J. "Film Boiling Heat Transfer from a Horizontal Surface as an Optimal Boundary Value Process," Proceedings of the Third International Heat Transfer Conference, Chicago, Ill., Aug. 1966. 29. Baumeister, K. J., Hamill, T. D., Schwartz, F. L., and Schoessow, G. J. "Film Boiling Heat Transfer to Water Drops on a Flat Plate," Paper presented at the 8th National Heat Transfer Conference, Los Angeles, Calif., Aug. 1965. 30. Hsu, Y. Y. and Westwater, Jo W. "Approximate Theory for Film Boiling on a Vertical Surface," Chemical Engineering Progress Symposium Series, 6_ No, 305, 15-24 (1960o) 31. Frederking, T.H.K. and Clark, Jo A. "Natural Convection Film Boiling on a Sphere " Advances in Cryogenic Eng:neering, 8, 501-506 (1963)o 32. Clark, J. A. and Merte, H. "Nucleate, Transition, and Film Boiling Heat Transfer at Zero Gravity," Paper presented at the 2nd Symposium on Physical and Biological Phenomena under Zero-G Conditions, Jan. 1963. 335. Merte, H. and Clark, Jo A. "Boiling Heat Transfer with Cryogenic Fluids at Standard, Fractional, and. Near-Zero Gravity, " Report IP-616, The University of Michigan, Industry Program of the College of Engineering, April 1963. 34. Pomerantz, M. L. "Film Boiling on a Horizontal Tube in Increased Gravity F-ields,"'Trans. ASME Journal_ of Heat Transfer, Series C, 86, 213-2:19 (1964)o

226 BIBLIOGRAPHY (Continued) 35. Heath, C. A. and Costello, C. P. "Some Effects of Geometry, Orientation and Acceleration on Pool Film Boiling of Organic Fluids," Trans. ASME Journal of Engineering for Industry3 Series B, 88, 17-23 (1966). 36. Class, C. R., DeHaan, J. R, Piccone, M., and Costq R. B. "Boiling Heat Transfer to Liquid Hydrogen from Flat Surfaces" Advances in Cryogenic Engineering, 5, 254-261 (1960)o 37. Strobridge, T, R. "The Thermodynamic Properties of Nitrogen from 64 to 3000K Between 0.1 and 200 Atmospheres," National Bureau of Standards Technical Note 129, Jan. 1962. 38. Goldsmith, A., Waterman, T. E., and Hirschhorn, H. J. Handbook of Thermophysical Properties of Solid Materials Volume I: Elements, The Macmillan Co., New York, 1961. 39. Scott, R. B. Cryogenic Engneeri.ng, D. Van Nostrand, Princeton, New Jersey, 1959. 40. Johnson, H. A., Editor, Boiling and Two-Phase Flow for Heat Transfer Engineers, A University of California Eng:ineering Extension Division lecture series held at Berkely and Los Angeles, May 27-28, 1965. 41. Johnson, VO J., Editor, "A Compendium of the Properties of Materials at Low Temperature (Phase I) Part I, Properties of Fluids," WADD Technical Report 60-56., Oct. 1960. 42. Frederking, T.H.K. Personal communication. 43. Hosler, E. R. and Westwater, J. Wo "Film Boiling on a Horizontal Plate," ARS Journal, 32, 553-558 (1962), 44. Seader, J. D., Miller, W. S., and Kalvinskas, L. A. "Boiling Heat Transfer for Cryogenics —Final Report," Rocketdyne Report R-5598, May 1964. 45. Manson, L. and Seader, J. D. "Study of.Boiling Heat Transfer with Lox9 LH2 and LN2 —Final Report," Rocketdyne Report R-6259, July 1965. 46. Chang, Y. P. "Wave Theory of Heat Transfer in Film Boiling," Trans. ASME Journal of Heat Transfer, Series C, 819 1-12 (1959). 47. Lienhard, J. Ho and Wong. P.T.Y. "The Dominant Unstable Wavelength and Minimum Heat Flux During Film Boiling on a Horizontal Cylinder," Trans. ASME Journal of Heat Transfer, Series C, 86, 220-226 (1964)o

227 BIBLIOGRAPHY (Concluded) 48. Bellman, R. and Pennington, R. H. "Effects of Surface Tension and Viscosity on Taylor Instability," Quarterly of Applied Mathematics, 12, 151 (1954). 49. Breen, B. PO and Westwater, J. W. "Effect of Diameter of Horizontal Tubes on Film Boiling Heat Transfer," Chemical Engineering Progress 58, 67-72 (1962). 50. Ellion, M. E. "A Study of the Mechanism of Boiling Heat Transfer," Jet Propulsion Laboratory Memorandum No. 20-88, Pasadena, Calif., March 1954. 51. Cess, R. D. and Sparrow, E. M. "Subcooled Forced-Convection Film Boiling on a Flat Plate," Trans. ASME Journal of Heat Transfer, Series C, 83 377-378 (1961). 52. Sparrow, E. M. and Cess, R. D. "The Effect of Subcooled Liquid on Laminar Film Boiling," Trans. ASME Journal of Heat Transfer, Series c, 84, 149-156 (1962). 53. Yang, W. J. "Phase Change of One Component Systems in a Container," A.I.Ch.E. 63-A-48. 54. Chang, Y. P. "A Theoretical Analysis of Heat Transfer in Natural Convection and in Film Boiling?" Trans. ASME, 7 150:1-11513 (1957). 55. Zuber, N., Tribus, M. and Westwater, J. W. "The Hydrodynamic Crisis in Pool Boiling of Saturated and Subcooled Liquid9s," Proceedings of the International Conference on Developments in Heat Transfer, ASMEg New York, 230-236 (1962)o 56. Clark, J. A. "Appendix Heat Transfer," To be published in Cryogenic Technology John Wiley and Sons, 1962. 57. Shapiro, A. o H The Dynamics and T:hermodynamics of Compressib2le Flu.id Fl1ow, Ronald Press, New York, NoYo9 1955. 58. Hoerner, SO Fluid Dynamic Drag, S. Hoerner, Midland Park, Noj,9 bL959. 59 Carslaw, H, SO, and Jaeger, J. CO Conduction of Heat in Solids, 2nd edition, Oxford University Press, London, 1959o