附面层抽吸对叶栅角区分离流动的控制研究

Investigation of Corner Separation Control for Cascade with Boundary Layer Suction

为研究附面层抽吸对叶栅角区分离流动的控制效果和机理,以高负荷轴流压气机叶栅为研究对象,基于数值方法深入分析了不同抽吸方案对叶栅角区流场的影响以及叶栅攻角特性随抽吸流量组合的变化规律。结果表明:不同抽吸方案对叶片通道中的分离流动的控制机理不同,进而会影响叶片负荷及扩压能力;将吸力面抽吸与端壁附面层抽吸结合起来的组合抽吸方案基本消除了位于叶栅吸力面的附面层分离和角区分离,叶栅叶型损失系数显著降低,在5°攻角下,当吸力面抽吸量为1.88%,端壁抽吸量为0.82%时,损失系数相较于原叶栅降低约63.8%;并且进一步研究发现各抽吸槽的抽吸流量均存在其最佳临界值;在进行组合抽吸时,应针对不同攻角工况,在其相应的临界值范围内选择合理的抽吸流量,以达到用较小的吸气量实现对叶栅分离流动的控制。

In order to study the effectiveness and mechanisms of boundary layer suction in controlling the corner separation,numerical simulations are carried out for a highly-loaded axial compressor cascade to investigate the effects of different suction schemes on the flow field around the corner and the change law of the incidence characteristics of cascade with the variation of the suction rate combination.The results show that different aspiration schemes have different effectiveness in controlling the flow separation,which leads to various influence on the blade loading and the diffusion abilities.The combined suction scheme fully remove both the sepatared flow on the blade suction surface and the three-dimensional hub corner separation.The profile loss coefficient is reduced significantly by 63.8%with the suction flow rate of 1.88%and 0.82%given for the slot on the blade suction surface and the slot on the end-wall respectively in the scheme of combined suction when incidence angle is 5°.And further work showed that the suction rate is not as great as possible.A reasonable suction flow rate should be selected within the corresponding critical value range for different incidence conditions in order to control the separation flow with a small suction.