Studies of Secondary Flow at Endwall of a Supersonic Compressor Cascade

Abstract

A combined experimental and numerical study was conducted to investigate the endwall secondary flow in a linear supersonic compressor cascade. The experiment was carried out in a supersonic wind tunnel, with Mach and Reynolds numbers (based on the blade chord) of 2.36 and 4.8 X 106, respectively. A three-dimensional viscous computational fluid dynamics (CFD) calculation was performed to simulate the endwall boundary layer and the three-dimensional secondary flows. The experimental and computational analyses presented are all at the design incidence angle. Experimental measurements include multiple-color surface oil flow visualization applied to the endwall and blade surfaces, blade-to-blade pitot pressure contours at the 90% chordwise position, and upstream and downstream static pressures at the endwall. All of these measurements compare favorably with the CFD calculation. Results from the CFD analysis show that endwall total-pressure losses in this supersonic compressor cascade are a significant contributor to the overall losses and can account for one-third of the overall flowfield loss.