Influence of mixed dimples on aerodynamic performance of high-load compressor cascade

In this study, the effect of mixed dimples on the aerodynamic performance of a high-load compressor cascade, named National Advisory Committee for Aeronautics 65-K48, at different attack angles was numerically and experimentally investigated. Mixed dimples with four columns and eight rows were arranged at 10% to 32% of the chord length of the half-blade height. The performance parameters of the cascade outlet section and vortex structure inside the cascade were exploited. The results reveal that the boundary layer is disturbed, and the boundary layer transition occurs ahead of time, induced by the mixed dimples. The anti-separation ability of the fluid was enhanced, and the separation bubbles on the suction surface were eliminated. Meanwhile, the lateral secondary flow was inhibited, and the intensities of the passage and concentrated shedding vortices were consequently reduced. Compared with the prototype cascade, the total pressure loss of the dimpled cascade at all attack angles was reduced. The total pressure loss can be reduced by nearly 20% at -9 degrees.