尾迹对低压涡轮端区非定常流动影响的数值研究

Numerical Investigation of Wakes on Endwall Unsteady Flow Inside Low Pressure Turbine

为提高尾迹对涡轮端区二次流影响的认识,利用尾迹降低端区损失,采用数值模拟方法对T106A非定常工况下的叶栅流动进行模拟,辅以实验进行校核。以上游尾迹对端区附面层的抬升作用和上游尾迹对叶栅通道前部涡系结构的破坏作用为切入点,分析尾迹对端区二次流非定常发展过程的影响。研究发现尾迹中心离开叶栅通道时,尾迹对叶栅端区二次流起抑制作用;当尾迹尾部离开叶栅通道时,尾迹卷起的轮毂附面层激励了端区二次流,使二次流更加活跃。

In order to understand the effects of the upstream wakes on the secondary flows and utilize wake to decrease total pressure loss in turbine endwall region,the numerical method is used to simulate the unsteady flow of T106A cascade.The numerical simulation results are validated by the experimental results.The unsteady development process of secondary flow under the influence of upstream wake in the endwall region is mainly deduced.That influence includes the up-lift effect of the upstream wakes on the endwall boundary layer and the destruction of the upstream wake on the vortex system structure in front of the cascade passage.It is found that the wake inhibits the secondary flows in endwall region as the center of the wake leaves the cascade outlet.Meanwhile,the wake rolls up the endwall boundary layer into the passage vortex as the tail of the wake leaves the cascade outlet,which results in the stimulation for secondary flows in the endwall region.