进口附面层对串列叶栅气动性能的影响研究

Effects of Inlet Boundary Layer on Aerodynamic Performance of Tandem Cascade

为探究进口附面层对串列叶栅气动性能的影响,以高亚声速压气机常规叶栅及其改型串列叶栅为研究对象,基于数值方法对比分析了不同进口附面层厚度对两叶栅的总体性能及三维角区分离的影响。结果表明:随着进口附面层厚度增加,原型叶栅三维角区分离范围沿展向逐渐增大,而串列叶栅三维角区分离范围的增加主要体现在周向。由于进口附面层的存在,串列叶栅前后叶片之间的缝隙射流与近端壁低能流体的相互作用所产生的通道涡、诱导涡及角涡是总压损失增大的主要原因。串列叶栅与原型叶栅相比能有效降低总压损失和提高静压升,然而附面层厚度的增加会减小这一优势;进口附面层厚度相对叶高的比值为0%,5%,12.5%时,串列叶栅的出口总压损失系数较原型叶栅分别降低11.1%,5.5%和4.1%,静压升系数分别提高7.4%,6.5%和6.4%。

In order to explore the effects of inlet boundary layer on the aerodynamic performance of the tandem cascade,a high-subsonic compressor conventional cascade and its modified tandem cascade were investigated with numerical method in the current paper.The impacts of different inlet boundary layer thickness on the overall performance of the two cascades and their three-dimensional(3D)corner separations were compared and analyzed.The results show that as the thickness of the inlet boundary layer increases,the 3D corner separation range of the original cascade gradually increases along the span direction,while the increase of the 3D corner separation range in the tandem cascade is mainly reflected in the circumferential direction.For the tandem cascade,due to the existence of the inlet boundary layer,the passage vortex,induced vortex and corner vortex caused by the interaction between the jet-flow from the gap of the front and rear blades and the low-energy fluid near the endwall have primary responsibility for the loss increasing.Compared with the original cascade,the tandem cascade can effectively reduce the total pressure loss and increase the static pressure rise,while the increase in the inlet boundary layer thickness will reduce the advantage.When the ratio of the thickness of the inlet boundary layer to the blade height is 0%,5%,and 12.5%,compared with the original cascade,the total pressure loss coefficient of the tandem cascade is reduced by 11.1%,5.5%,and 4.1%,respectively,and the static pressure rise coefficient increases by 7.4%,6.5% and 6.4%,respectively.