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Physics   > Home   > Entropy: Thermodynamics – Energy – Environment – Economy   > Issue 3   > Article

The efficiency of turbomachinery in the zero- and three-dimensional approaches

Deux méthodes de détermination de l’efficacité des turbomachines dans des approches 0D et 3D


Paweł Ziółkowski
Gdańsk University of Technology
Poland

Tomasz Kowalczyk
Institute of Fluid Flow Machinery Polish Academy of Sciences
Poland

Janusz Badur
Institute of Fluid Flow Machinery Polish Academy of Sciences
Poland

Michel Feidt
University of Lorraine
France



Published on 4 March 2021   DOI : 10.21494/ISTE.OP.2021.0620

Abstract

Résumé

Keywords

Mots-clés

Efficiency of turbomachinery is usually defined using an isentropic process. This approach provides a reliable reference point only when pressure and temperature measurements are available, e.g. at the casing inlet and outlet. In the case of a single stage internal efficiency determination the reference point is difficult. Computational fluid dynamics allows for an exact calculation of values of losses occurring in a turbine stage from turbine blades geometry, clearances, uneven steam distribution and other. Present method is a three-dimensional polytrophic approach based on work comparison of a turbine stage using real and ideal working fluid. The reference state is estimated by iterative simulation of considered geometry using the Eulerian model of compressible fluid. This approach is more convenient and feels natural when using 3D modeling. Moreover, calculations conducted for a control stage indicated differences between results attained using those two approaches less than 0.2%.

Efficiency of turbomachinery is usually defined using an isentropic process. This approach provides a reliable reference point only when pressure and temperature measurements are available, e.g. at the casing inlet and outlet. In the case of a single stage internal efficiency determination the reference point is difficult. Computational fluid dynamics allows for an exact calculation of values of losses occurring in a turbine stage from turbine blades geometry, clearances, uneven steam distribution and other. Present method is a three-dimensional polytrophic approach based on work comparison of a turbine stage using real and ideal working fluid. The reference state is estimated by iterative simulation of considered geometry using the Eulerian model of compressible fluid. This approach is more convenient and feels natural when using 3D modeling. Moreover, calculations conducted for a control stage indicated differences between results attained using those two approaches less than 0.2%.

efficiency entropy CFD zero-dimensional three-dimensional turbine stage isentropic polytrophic

efficiency entropy CFD zero-dimensional three-dimensional turbine stage isentropic polytrophic