基于LES的压气机叶栅通道非定常流动结构研究

In order to further understand the unsteady flow structure in compressor cascade passage, the effects of the thickness of incoming flow boundary layer and solidity changes on the vortex structure and the total pressure loss coefficient in cascade passage were studied by large eddy simulation (LES) method. The results show that the thickening of the incoming flow boundary layer leads to the decrease of the axial kinetic energy of the fluid at the endwall, which makes the pressure surface branch of the horseshoe vortex flow to the suction surface of the adjacent blade earlier; when the boundary layer of incoming flow is thicker, the height of passage vortex spanwise uplift along the trailing edge of cascade is higher, and the range of corner separation is larger; the total pressure loss of cascade increases with the thickening of boundary layer, especially the boundary layer loss and the secondary flow loss; when the solidity is low, the separation on the cascade suction surface will affect the passage vortex and the range of corner separation ; with the increase of solidity, the transverse pressure gradient decreases, the velocity distribution of cascade passage is more uniform, the intensity and scale of passage vortex decrease, and the range of corner separation decreases; when the flow on the blade surface is no longer separated because of the increase of solidity, the total pressure loss is significantly reduced, but the friction loss between the air flow and the blade surface will increase with the increase of solidity.