动叶栅倒角对透平级气动性能的影响

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.

Influence of rotor blade fillets on turbine stage performance

The rotor blade in the first stage of Aachen turbine was added with fillet structure and a full three-dimensional viscous numerical simulation was performed to analyze the influence of rotor fillet on the performance of the turbine stage and the flow fields under the stage environment. The results indicate that the efficiency decreased significantly when the angle formed between fillet and end wall become over small, which should be taken into account in the manufacture process of the rotor blade. The structure of fillet decreased the transverse pressure difference near the rotor hub and shroud, and shifted the aerodynamic load to the downstream part of the rotor blade. The filletes 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 were close to the midspan of the rotor due to the influence of the fillet which increased the strength of the corner vortex and the loss of secondary flow near the rotor endwalls.