尾缘S3面积比梯度对涡轮后机匣的影响

Influence of S3 area ratio gradient at trailing edge on turbine rare frame

针对整流叶栅与支板融合设计中难以采用三维叶片造型对二次流进行控制的情况,开展对涡轮后机匣内部整流叶栅尾缘S3面积比梯度的研究。以某1.5级涡轮为例,通过数值模拟的方法,对比三种设计的内部流场和气动性能,验证了降低尾缘S3面积比梯度控制角区二次流的方法。结果显示:尾缘S3面积比梯度从0.01降低到-0.05时,整流叶栅总压恢复系数从0.979升高到0.991,5%展高处S参数从0.011降低到0.005,吸力面和轮毂端壁处的回流区消失,角区分离得到有效控制;尾缘S3面积比梯度从-0.05降低到-0.10时,吸力面角区流动速度增加,5%展高处S参数不再变化、堵塞程度降低、轴向密流比(AVDR)升高、总压恢复系数升高。

For the intergraded design of support plate and outlet guide vane,where it’s difficult to apply the three-dimensional blade design,the secondary flow in the outlet guide vane can be controlled by changing S3 area ratio gradient at the trailing edge.The numerical results of inner flow field and aerodynamics performance of three designs were compared in a 1.5 stage turbine.The results showed that when the gradient reduced from 0.01 to-0.05,the overall total pressure recovery coefficient of the outlet guide vane increased from 0.979 to 0.991,and the S parameter on 5%span reduced from 0.011 to 0.005.The back-flow zone on the hub endwall and the suction side of the blade disappeared,and the corner separation was effectively controlled.When gradient reduced from-0.05 to-0.10,the flow velocity in the corner zone increased,and at the 5%span,corner blockage lessened,axial velocity density ratio(AVDR)increased,total pressure recovery coefficient increased,yet the S parameter didn’t change.