上游尾迹与涡轮转子泄漏流相互作用数值模拟

叶轮机内部流动本质上是周期性非定常的,研究涡轮转子叶尖区域的非定常相互作用机理,对提高小展弦比高负荷涡轮性能具有重要意义.利用数值模拟方法研究了上游静子尾迹与涡轮转子叶尖泄漏流的非定常相互作用,分析了定常结果、时间平均结果以及瞬时时刻结果的流动图画.结果表明:上游静子尾迹与涡轮转子尖区二次流的相互作用能明显影响泄漏涡和机匣通道涡的时空演化规律,从而改变转子尖区的损失分布.上游尾迹在转子通道中传播时,诱导泄漏涡和通道涡区域出现周期性的扰动涡对,扰动涡对沿着泄漏涡和通道涡的轨迹向下游运动,使得转子尖区二次流结构呈现周期性变化. 

Numerical simulations of upstream wake-tip leakage vortex interactions in turbine rotor

The internal flow of turbomachinery is intrinsically unsteady, so investigating the unsteady interactions in the tip region of turbine rotor are meaningful for improving the performance of low aspect/high loading turbine. The upstream wake-tip leakage vortex interactions in a turbine rotor were simulated by a 3-D unsteady viscous solver. The flow diagrams of steady, time-averaged and transient results were analyzed. The results indicate that the unsteady interactions between the upstream wake and the rotor tip regions have changed the spatio-temporal evolution of the tip leakage vortex and the passage vortex, consequently the loss is changed. Due to the wakes the tip leakage vortices and the passage vortices are separated into periodic perturbation counterrotating vortices. These counterrotating vortices move downstream along the tip leakage vortex path.