Effect of tip geometry and tip clearance on aerodynamic performance of a linear compressor cascade

The tip leakage flow between a blade and a casing wall has a strong impact on compressor pressure rise capability, efficiency, and stability. Consequently, there is a strong motivation to look for means to minimize its impact on performance. This paper presents the potential of passive tip leakage flow control to increase the aerodynamic performance of highly loaded compressor blades. Experimental investigations on a linear compressor cascade equipped with blade winglets mounted to the blade tips have been carried out. Results for a variation of the tip clearance and the winglet geometry are presented. Current results indicate that the use of proper tip winglets in a compressor cascade can positively affect the local aerodynamic field by weakening the tip leakage vortex. Results also show that the suction-side winglets are aerodynamically superior to the pressure-side or combined winglets. The suction-side winglets are capable of reducing the exit total pressure loss associated with the tip leakage flow and the passage secondary flow to a significant degree.