LAUSR

Abstract Three-dimensional corner stall is one of the key factors limiting the compressor performance. This paper presents a detailed experimental and computational study of a flow control strategy involving the endwall suction, aiming to eliminate the hub corner stall in a highly loaded axial compressor cascade. Various mass flow suction cases were parametrically tested with the aim of eliminating the corner stall by applying a minimum suction flow ratio. In the experiments, seven-hole pressure probe traverses, different loading distributions and surface oil flow visualizations were applied to address the flow and loss mechanisms in the cascade. Measurements were supplemented with numerical predictions from a commercially available CFD code. It was found that the corner stall, characterized by a large amount of reversed fluid, occupied a large region over the blade suction surface in the highly loaded compressor airfoil, rather than occurring at the junction of a blade suction surface and the endwall as in the conventionally loaded compressor airfoil. By applying flow control, the dominant flow structures, e.g. the flow separations and particularly the corner stall, within the compressor cascade were significantly affected. The maximum spanwise penetration depth of the endwall flow on the suction surface was significantly decreased once the endwall suction flow was applied. Furthermore, the corner stall was completely eliminated by suctioning the mass flow at a specific ratio of the inlet boundary layer flow rate. The midspan flow field was not notably affected, and a further increase in suction mass flow did not benefit the flow field approaching the endwall.