Experimental investigation of end-wall VGJs in a compressor cascade

Highlights: • Experiments are conducted in a high subsonic compressor cascade. • Vortex generator jets are used to control flow separation. • Control effect of VGJs is studied at off design points. • The influence of jet flow rate is studied. • The oil-flow visualization is used to obtain the change of the flow pattern. One of the important ways of improving compressor performance is to control three-dimensional (3D) separations which are related to the end-wall cross flow and corner separation. End-wall VGJs has been applied on the leading edge of the blade within a high subsonic compressor cascade to control the separation. Flow-control experiments are conducted in a high-speed wind tunnel with an instrumented NACA0065-k48. Detailed aerodynamic parameters are collected using a five-hole pressure probe and pressure tabs. Additionally, oil-flow visualization is used to obtain the topology of the flow field. Jet to inlet mass flow ratio is studied both in design and off design condition. The experimental results show that the VGJs cause a significant loss reduction both in design and off design condition. The control effect is more obvious with the increase of jet mass flow. The uniformity of the outlet flow and the static pressure rise are also improved. From the results of the oil flow experiment, the separation onset is delayed and the range of the reverse flow zone is also reduced, but the flow structure on the suction surface is almost unchanged.