一种复合方法抑制叶尖泄漏的试验及模拟研究

为了强化涡轮叶顶间隙泄漏抑制，提出了将被动式气动封严与叶尖几何改型方法相结合用于抑制叶尖泄漏及其损失的流动调控新方案。对叶顶凹槽与自发射流耦合的3种典型方案进行了模型试验和数值模拟，探讨了2种被动式抑制方法的耦合机理。研究表明，叶顶凹槽与自发射流（STI）之间存在明显耦合作用，当自发射流出口位于凹槽底部时，自发射流与凹槽涡（GV）预先掺混，导致2种抑制效应相互抵消，无法对泄漏流形成有效抑制，为不良耦合。而当自发射流出口位于凹槽压力边或吸力边时，自发射流的反吹阻滞效应与凹槽涡的动能耗散效应相叠加，对泄漏流形成2次有效封堵，为有效的耦合方案，而且以自发射流出口位于凹槽吸力边时，对泄漏流的抑制效果最佳。

Experiment and simulation study on tip leakage suppression by a compound method

To reduce the tip leakage and flow loss of gas turbine, the new method of pneumatic seal combined with tip structure modification was put forward based on flow reorganization. Three typical combination schemes of tip groove and spontaneous tip injection were investigated by model test and numerical simulation. The coupling mechanism of the two passive suppression methods was discussed. The results show that the coupling effects between tip groove and spontaneous tip injection (STI) are obvious. When the outlet of STI locates at the base of the groove, strong mixing occurs between the STI and the groove vortex (GV), which deteriorates the suppression effect for both of them, and cannot suppress the leakage flow effectively, so it is not a good coupling scheme. When the outlet of STI locates on the top of rib, neither on pressure side or suction side, the effect of counter blowing by STI and kinetic energy dissipation by GV can add up to generate twice effective seal, meaning that they are effective coupling schemes. In particular, when the outlet of STI locates on the top of suction-side-rib, the suppression effect on leakage flow is the best.