Method for analyzing flow losses in turobmachinery by using the measured results of stereoscopic particle image velocimetry

A method of calculating the entropy production rate based on the measured velocity flow field was established based on the similar processes between SPIV measurement and large eddy simulation (LES). Comparing the turbulence dissipation rate estimated by several typical subgrid-scale (SGS) stress models, it can be found that the result calculated by the mixing model is most reasonable; however, the coefficients C_Sm and C_Am should be well determined. Using the mixing model the entropy production rate of the complex flow fields near the rotor tip region measured by SPIV were analyzed. The results show that at the design condition the losses are mainly caused by the tip leakage vortex, while at the near-stall condition both the tip leakage vortex and the corner vortex can bring large flow losses.