动叶栅倒角对透平级气动性能的影响

Influence of rotor blade fillets on turbine stage performance

对Aachen透平第一级动叶栅添加倒角结构,应用全三维黏性数值模拟方法,分析了级环境下动叶栅倒角对透平级性能和内部流场的影响.结果表明：过小的倒圆夹角会明显降低透平级效率,在叶栅加工中应给予足够重视;倒角结构降低了动叶根、顶处横向压差,气动负荷向动叶栅后半部分转移;动叶根部和顶部倒角对流场的影响主要分布于0%~55%和70%~100%叶高范围内,受倒角影响上、下通道涡向叶栅中部靠近,端壁处角涡强度增大,次流损失上升.

The rotor blade in the first stage of Aachen turbine was added with a fillet structure,and a full three-dimensional viscous numerical simulation was performed to analyze the influence of rotor fillet on the performance of turbine stage and flow fields under the stage environment.The results indicate that the efficiency decreases significantly when the angle between fillet and end wall becomes too small,which should raise more attention in the manufacturing process of rotor blade.The fillet structure decreases the transverse pressure difference near the rotor hub and shroud,and shifts the aerodynamic load to the latter half part of the rotor blade.The fillets at hub and shroud affect the flow field of the rotor mainly at the 0%~55% span and the 70%~100% span,respectively.The upper and lower passage vortexes are close to the midspan of rotor due to the influence of the fillet,leading to increase of the intensity of corner vortex and the loss of second flow near the endwall.