Experimental study of the effect of different gap height on the highly-loaded compressor cascade flow characteristics

The flow characteristic of highly-loaded compressor cascade in different gap height conditions were investigated experimentally in a low-speed plane cascade wind tunnel. The distributions of the exit secondary flow vector and the exit aerodynamic parameters were measured by five-hole probe in detail. Also, the ink-trace flow visualizations on the cascade surface and lower endwall were performed. The results show that the increase in tip clearance exacerbated the Interaction and blending between leakage flow passage and vortex. Thus, the structure and shape of the secondary flow in the flow channel between the cascades changed; The increase in tip clearance could completely inhibited the corner separation from suction surface. Low energy fluid which was taken away by clearance leakage flow was brought to the trailing edge and its downstream position. The above condition exacerbated flow separation in some corresponding situations; Leakage flow will cause a significant reduction for the total loss of the cascade. The extent of the loss is not necessarily proportional to the gap height.