The paper examines the thermodynamic processes of a helical screw-expander that operates with dry saturated steam at its inlet. The work output of the screw-expander is analysed using a simple ‘pseudo-polytropic’ index. Using the available experimental data from the literature, an empirical model for the prediction of work using the ‘pseudo-polytropic’ indices is formulated. The expansion indices are expressed in terms of built-in volumetric and pressure ratios; how they are formulated is usually given in an expander specification. Based on the empirical model, there is a good agreement between the experimental work and the predicted values.
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References
1.
WilsonS. S.RadwanM. S.An appropriate thermodynamics for heat engine analysis and design. Int. J. Mech. Educ., 1977, 5(1).
2.
SmithI. K.MartinP. R.Power from low grade heat sources. Project Sphere—an evaluation of the trilateral wet-vapour cycle. Chart. Mech. Engr., January 1985.
3.
Screw type steam engine, October 1984, Mayekawa Manufacturing Company Limited, 2–13–1 Botan Koto-Ku, Tokyo 135, Japan.
4.
SilverR. S.An introduction to thermodynamics, 1971 (Cambridge University Press).
5.
RogersG. F. C.MayhewY. R.Engineering thermodynamics—work and heat transfer, 2nd edition, 1967 (Longman, London).
