Sensitivity Of Compressor Performance And Tipleakage Vortices To Inhomogeneous Casing Heatflux Distributions

Compressor cooling is a promising method for increasing the efficiency of aero engines. This paper shows that the application of this method is not limited to the thermodynamic effect of extracting the net heat flow, but also extends to the heat-flux distribution provided by the cooling. To demonstrate this, we conducted an extensive numerical study featuring a wide range of heating and cooling distributions applied to the casing of a compressor rotor in a single-stage model, which was taken from the last stage of an experimentally validated four-stage high-speed compressor model. The results show that the benefit – or detriment – of these variations may be significantly impacted by the heat-flux distribution applied. We show that, while the net heat flux proves to be the dominant factor, the local distribution may account for up to 14% in the mass-flow variability and up to 21% of the variation in the adiabatic rotor efficiency. The results suggest an influence of the heat-flux distribution on the tip-leakage vortex.