Laser-In-Situ Monitoring of Combustion Processes

Abstract

Several examples of laser in situ monitoring of combustion processes are presented. Using a frequency modulated 13CO2 waveguide laser, in situ concentrations of NH3 down to 1 ppm were measured at temperatures up to 600°C in waste incinerators and power or chemical plants. Following ignition of CH3OH-O2 mixtures by a TEA CO2 laser, gas temperature profiles were measured using rapid scanning tunable diode laser spectroscopy of CO molecules. In laminar CH4-air counterflow diffusion flames at atmospheric pressure absolute concentrations, temperatures, and collisional lifetimes of OH radicals were determined by 2-D and picosecond LIF and absorption spectroscopy. Two-dimensional LIF and Mie scattering were used to observe fuel injection and combustion in a diesel engine.