大弯角开槽叶栅槽道位置与结构研究

In order to widen the usable range of incidence angle of the large camber high-load cascade and optimize the flow separation structure of the suction surface of the blade, a large camber cascade was selected as the research object. The cascade blade was treated with a double 'C' slot structure, which was opened from the pressure surface to the suction surface. Keeping the length of the slot and other slot parameters unchanged and setting the four exit positions of 70%, 75%, 80% and 85% of axial chord length, the effects of the slot exit position on the performance of the cascade were studied. It is found that, under specific incidence angle, the optimal slot exit position, which controls well the flow separation on suction surface, is located after the suction surface starting point of hub corner separation line and before the trailing edge separation line. In the full range of incidence angles, the optimal slot exit position corresponds to the exit position at 0° incidence angle. In order to reduce the total pressure loss in slot, an improved structure of the 'SC' shaped slot was proposed, which was compared with double 'C' shaped slot and prototype cascade when the slot exit position is 80% axial chord length. The results show that compared with the double 'C' shaped slot structure, the 'SC' shaped slot structure reduces the total pressure loss in the slot and cascade wake loss, increases the air jet velocity at the slot exit and the static pressure at the trailing edge of the blade. In addition, compared with the prototype cascade, 'SC' shaped slot structure can effectively reduce the total pressure loss in full range of incidence angles, and basically removes the boundary layer separation on the blade suction surface, weakens the hub corner separation, and improves the diffusing capacity of the cascade.