Experimental Investigations on Tip Leakage Flow and Noise in Skewed Blades

PIV Experiment and pressure test of tip leakage flow of circumferential skewed axial fans were carried out under design and off-design conditions. Two circumferential skewed fans and a radial fan were investigated in this study. Aerodynamic and aeroacoustic performances were measured, and detailed flow field using PIV were measured in the region of tip leakage. The development of tip leakage vortex was analyzed through the PIV results. And the results showed that the tip leakage vortex for the forward-skewed blade is more stable. The pressure test on the casing and the far free field noise test gained the tip leakage noise component. And the results showed the forward skewed blade is found to be effective in eliminating noise source in the tip clearance region and in controlling tip leakage flow to expand the stall-free operation range under off-design conditions.