Cavitation in a bulb turbine
dc.contributor.author | Necker, J. | en_US |
dc.contributor.author | Aschenbrenner, T. | en_US |
dc.contributor.author | Moser, W. | en_US |
dc.date.accessioned | 2011-05-26T17:39:12Z | |
dc.date.available | 2011-05-26T17:39:12Z | |
dc.date.issued | 2009-08 | en_US |
dc.identifier | CAV2009-91 | en_US |
dc.identifier.uri | https://hdl.handle.net/2027.42/84277 | en_US |
dc.description.abstract | The flow in a horizontal shaft bulb turbine is calculated as a two-phase flow with a commercial Computational Fluid Dynamics (CFD-)-code including cavitation model. The results are compared with experimental results achieved at a closed loop test rig for model turbines. On the model test rig, for a certain operating point (i.e.volume flow, net head, blade angle, guide vane opening) the pressure behind the turbine is lowered (i.e. the Thomacoefficient s is lowered) and the efficiency of the turbine is recorded. The measured values can be depicted in a so-called s?break curve or h-s?diagram. Usually, the efficiency is independent of the Thoma-coefficient up to a certain value. When lowering the Thoma-coefficient below this value the efficiency will drop rapidly. Visual observations of the different cavitation conditions complete the experiment. In analogy, several calculations are done for different Thoma-coefficients s and the corresponding hydraulic losses of the runner are evaluated quantitatively. Besides, the fraction of water vapour as an indication of the size of the cavitation cavity is analyzed qualitatively. The experimentally and the numerically obtained results are compared and show a good agreement. Especially the drop in efficiency can be calculated with satisfying accuracy. This drop in efficiency is of high practical importance since it is one criterion to determine the admissible cavitation in a bulbturbine. The visual impression of the cavitation in the CFDanalysis is well in accordance with the observed cavitation bubbles recorded on sketches and/or photographs. | en_US |
dc.relation.ispartofseries | CAV2009 - 7th International Symposium on Cavitation, 16-20 August 2009, Ann Arbor, MI | en_US |
dc.title | Cavitation in a bulb turbine | en_US |
dc.type | Article | en_US |
dc.contributor.affiliationother | Voith Hydro Holding; Voith Hydro Holding; Voith Hydro Holding | en_US |
dc.description.bitstreamurl | http://deepblue.lib.umich.edu/bitstream/2027.42/84277/1/CAV2009-final91.pdf | |
dc.owningcollname | Mechanical Engineering, Department of |
Files in this item
Remediation of Harmful Language
The University of Michigan Library aims to describe library materials in a way that respects the people and communities who create, use, and are represented in our collections. Report harmful or offensive language in catalog records, finding aids, or elsewhere in our collections anonymously through our metadata feedback form. More information at Remediation of Harmful Language.
Accessibility
If you are unable to use this file in its current format, please select the Contact Us link and we can modify it to make it more accessible to you.