端壁抽吸对跨声速转子流动特性影响研究

Investigation on Effects of End Wall Boundary Layer

关键词:  跨声速转子  流动控制  端壁抽吸  角区分离

Key words:  Transonic rotor  Flow control  End-wall boundary layer suction  Corner separation

摘要:

针对NASA的Rotor 67进行数值模拟以揭示轮毂角区边界层分离诱发机制和进一步完善角区分离控制方法。数值结果表明，角区边界层在强逆压梯度和叶片后半段较大曲率变化的双重影响下引发了分离。通过对比分析不同抽吸方案对角区流动的影响发现，在轮毂90%弦长位置处采用边界层抽吸，且相对抽吸流量为0.14%时，可完全消除轮毂角区内的回流流体和脱落涡结构，抽吸效果最佳。在保证转子压比基本不变的情况下，最大可使得转子效率提高0.29%，落后角减小4°。轮毂抽吸还抑制了叶根附近低能流体堆积效应，有助于改善叶片载荷分布和出口气流参数的分布。

Abstract:

The numerical simulations have been carried out on Rotor 67 to explore the mechanism of flow separation in corner near hub and improve the effects of control method for corner separation. The numerical results show that both the stronger negative gradient and larger curvature change approaching trailing edge of rotor lead to corner separation. In comparison with the effects of different boundary layer suction location on corner flowfields，the optimal scheme，with which the suction location is at the 90% of chord length and the relative suction rate is 0.14%，completely eliminates the backflow in corner region and detached vortex near hub. While the maximum increase of 0.29% for rotor efficiency and a reduction of 4° for deviation angle are presented in this new scheme，with the pressure ratio maintaining constant. In addition，the accumulation of low energy fluids near hub has been attenuated obviously in the optimal scheme for hub boundary layer suction，which benefits to improve the distribution of blade loading and outlet flow parameters in rotor.