Effects of boundary layer suction on the flow characteristic in a highly-loaded compressor cascade with clearance

Boundary layer suction is applied to stator cascade with clearance in a highly-loaded compressor. In a low-speed plane cascade wind tunnel, effects of boundary layer suction on the flow characteristic in a highly-loaded compressor cascade with stator clearance were studied. The exit section aerodynamic parameters were measured by five-hole aerodynamic probe, and the distributions of the exit secondary flow vector were obtained. Also, the ink-trace flow visualizations on the cascade surface and lower endwall were performed to show the boundary layer development. The results show that three-dimensional separated flow can be greatly improved and flow loss was decreased when boundary layer suction was adopted appropriately. Boundary layer suction was applied to the regions of low endwall which is near suction surface of blade and in the gap (case 1, case 2 and case 4 in this paper). Thus, the kinetic energy of the leakage flow got weakened and then the length and position of suction surface's reattachment line and endwall separation line were influenced. In the corresponding region, three-dimensional separated flow got in control. As a consequence, the total loss was greatly decreased, especially case 1's loss declined by 20.8%.