超跨声速风扇中叶尖间隙影响的两种机制

Two Mechanisms of Tip Clearance Effect in Super Transonic Fan

以带进口导叶的某跨声速高负荷高速单极风扇为研究对象,以转子尖部叶栅前缘半径量化叶尖间隙,相对叶尖间隙范围为0~4。采用NUMECA软件,基于S-A湍流模型进行数值模拟。计算结果表明:相对叶尖间隙为0.1时风扇综合性能最佳;尖部叶栅通道内激波后有附面层分离的低速流与泄漏流两类流动;当相对叶尖间隙在0~4范围内变动时,附面层分离逐渐被抑制,泄漏流逐渐增强;当相对叶尖间隙小于1时附面层分离的低速流占主导;当相对叶尖间隙大于1时泄漏流占主导;当相对叶尖间隙等于1时激波后的流动从附面层分离低速流过渡到泄漏流状态。

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.