Exergetic analysis of the nasa rotor 37 compressor test case

Authors

Ilyès Berhouni  - ONERA - The French Aerospace Lab, France
Ilias Petropoulos - ONERA - The French Aerospace Lab, France
Didier Bailly - ONERA - The French Aerospace Lab, France

Abstract

Standard performance indicators used for turbomachine flows rely on total pressure and temperature ratios evaluated at fixed stations of the configuration under investigation. These provide a quantification of overall performance, yet do not allow to explicitly anal- yse losses with a clear link to their physical source. For this reason, the exergy analysis is of particular interest in turbomachinery performance analyses as it quantifies reversible and irreversible losses through exergy outflow and anergy generation respectively, with these terms being associated to physical phenomena. An additional advantage of this ap- proach is the consideration of both mechanical and thermal effects. A new exergy balance adapted to rotating frames of reference was recently presented and validated by ONERA on a propeller configuration with the in-house post-processing software F F X. This paper will present the application of this formulation to the exergy analysis of the NASA Rotor 37 compressor test case. More specifically, it is used to investigate its performance in the exergy framework for different operating regimes. Attention is given to the decomposi- tion of irreversible losses due to shockwaves, viscous and thermal effects. In addition to integral values, visualizations of anergy fields give a physical insight into the local loss mechanisms involved. A case with an isothermal rather than adiabatic casing will then be studied to investigate the impact of such a boundary condition on the exergy outflow and anergy generated. The evolution of flow physics along the channel will be investigated by variation of the exergy balance control volume. A comparison is planned between the reference and an in-house optimized NASA Rotor 37 geometry, aiming at giv- ing a clearer insight into the sources of performance improvement. Finally, the numerical accuracy of the exergy balance at the discrete level will also be discussed.