Altering the volumetric expansion ratio of a Lysholm helical screw expander
This is an analysis of the effects of the volumetric expansion ratio on the operation of a Lysholm helical screw expander. Extensive testing of the University of California Lysholm engine with a 5.3 volumetric expansion ratio was performed. In this experiment, the expansion ratio has been reduced from 5.3 to 4.0. Tests were performed at a variety of speeds and qualities for a 5.0 pressure ratio and at a variety of speeds and pressure ratios for 99 percent quality. It was predicted that decreasing the volumetric expansion ratio would decrease the leakage fraction and thereby increase efficiency. This occurred as predicted. Isentropic efficiency increased 20 percent for 50 percent quality steam and 16 percent for 33 percent quality steam, all for an inlet pressure of 120 psia and a speed of 9000 rpm. A maximum efficiency of 47.2 percent was reached at 33 percent quality, 9000 rpm and a pressure ratio of 5.0. It was noted that the leakage rate did not appear to be a function of expansion ratio, as had been expected. Using this fact the previous empirical models of the engine were extended to include volumetric expansion ratio as a variable parameter.
- Research Organization:
- California Univ., Berkeley (USA). Coll. of Engineering
- DOE Contract Number:
- AT03-80ET27252
- OSTI ID:
- 6771079
- Report Number(s):
- DOE/ET/27252-T3; ON: DE84013695
- Resource Relation:
- Other Information: Portions are illegible in microfiche products. Thesis
- Country of Publication:
- United States
- Language:
- English
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