Sage Journals: Discover world-class research

Abstract

A method of accounting for losses and defining efficiencies in the blade rows of adiabatic turbomachinery stages is described. This is based on the concept of specific dissipation work which is the integral of the product of local temperature and entropy change due to the losses (∫ T ds). This formulation allows various entropy-based efficiencies and loss coefficients to be derived with equations that are exact for all types of fluid (liquids, ideal gases, and real gases). The expressions for the polytropic and isothermal efficiency, as well as for the Markov blade row loss coefficient, resulting from this can be directly visualized in a Mollier chart (h-s diagram) as the ratio of entropy and enthalpy changes between two real states and a single virtual state.

Keywords

efficiency losses turbomachinery

Get full access to this article

View all access options for this article.

References

Casey

M. V.

Roth

A streamline curvature throughflow method for radial turbocompressors. IMechE Conference C57/84, 1984.

Dixon

S. L.

Fluid mechanics and thermodynamics of turbomachinery, 5th edition, 2005 (Elsevier, Oxford).

Schulz

J. M.

The polytropic analysis of centrifugal compressor stages. Trans. ASME, J. Eng. Power, 1962, 84, 69–82.

Zweifel

The determination of the variation of state in turbomachinery by means of the increase in entropy. Brown Boveri Rev., 1941, 28(8/9), 232–236.

Traupel

Thermische Turbomaschinen, 4th edition, 2001 (Springer, Berlin).

Fister

Fluidenergiemaschinen, vol. 1, 1984 (Springer, Berlin).

Baehr

H. D.

Thermodynamik, 11th edition, 2004 (Springer, Berlin).

Horlock

J. H.

Losses and efficiencies in axial-flow turbines. Int. J. Mech. Sci., 1960, 2, 48–75.

Brown

L. E.

Axial flow compressor and turbine loss coefficients: A comparison of several parameters. ASME, J. Eng. Power, 1972, 95, 195–201.

10.

Horlock

J. H.

Axial compressors, 1958 (Butterworth, London), reprinted with additional material in 1973 (Krieger Publishing Co., Florida).

11.

Horlock

J. H.

Axial flow turbines, 1966 (Butterworth, London).

12.

Whitfield

Baines

N. C.

Design of radial turbomachines, 1990 (Longman, John Wiley and Sons, London).

13.

Lüdtke

K. H.

Process centrifugal compressors, 2004 (Springer, Berlin).

14.

Denton

J. D.

Loss mechanisms in turbomachines. The 1993 IGTI scholar lecture. Trans. ASME, J. Turbomach., 1993, 115, 621–656.

15.

Greitzer

E. M.

Tan

C. S.

Graf

M. B.

Internal flow: concepts and applications, 2004 (Cambridge University Press, Cambridge).

16.

DIN 4319. Steam and gas turbines, thermodynamic and gas dynamic terms for steam and gas turbines; basic principles, Part 1. Deutsches Institut fur Normung, 1994.

17.

Barbarin

V. I.

Mikirtichan

V. M.

The entropic efficiency of compressors and turbines. Fluid Mech. - Soviet Res., 1982, 11(3), 36–47.

Accounting for losses and definitions of efficiency in turbomachinery stages

Abstract

Abstract

Keywords

Get full access to this article

References