Determining the entropy generated in a low reynolds number compressor cascade based on the wake velocity profile

The entropy generated in a compressor cascade at low Reynolds number was determined from the wake velocity profile. Accurately predicting the turbomachinery stage efficiency is one of the more challenging problems in propulsion due to the complexity of the flow field. Rather than conduct turbomachinery tests under full scale high temperature rotating flow conditions, a better understanding of some of the root causes of loss, in the form of entropy generated, may be obtained through two-dimensional cascade measurements. An experimental and computational study was conducted to determine the entropy generation rate based on the wake velocity profile at a chord Reynolds number of 8,500. The wake results were in good agreement with results for the entropy generation rate based on more detailed boundary layer measurements made along the blade surface. Results show that the amount of entropy generated increases with increasing solidity and increasing stagger angle.