超跨声速风扇中叶尖间隙影响的两种机制

Taking a certain transonic high-load and high-speed single-stage fan with its inlet guide vane as the research object, the tip clearance was quantified by the cascade leading edge radius of the blade tip of the rotor, and the relative tip clearance range was from 0 to 4. The NUMECA software was used to carry out a numerical simulation based on the S-A turbulence model. The calculation results show that the overall fan performance is optimal when the relative tip clearance is 0.1, and there are two kinds of flow at the rear of shock wave in the tip cascade passage, including the low speed flow of the boundary layer separation and the leakage flow.When the relative tip clearance is less than 1, the low speed flow of the boundary layer separation is dominant; while the relative tip clearance is greater than 1, the leakage flow takes the leading role; when the relative tip clearance is equal to 1, the flow at the rear of the shock wave is in the transition state from the low speed flow of the boundary layer separation to the leakage flow.