周期性尾迹对涡轮端区二次流强度影响

为进一步认识上游周期性尾迹对涡轮端区流动的影响,分析尾迹与端区二次流结构之间的相互作用,基于高负荷低压涡轮叶型Packb对非定常工况下尾迹与端区流动进行了数值模拟研究,并借助扇形叶栅实验台进行辅助校核。数值研究采用商业CFD软件进行仿真,借助LES模型耦合Smagorinsky亚格子模型,对尾迹造成的端区流动影响进行了分析。研究表明,尾迹的存在使得叶栅出口处的端区二次流强度出现周期性的变化,其增强与削弱作用的交替出现是尾迹在通道中所处位置不同所造成的,利尾迹周期性地对二次流强度的削弱作用可有效减小端区流动损失。

The Influence of Wakes on Turbine Endwall Secondary Flow

In order to further understand the impact of upstream periodic wakes on the endwall flow and the interaction between the secondary flow structure, a high-lift low pressure turbine(LPT)cascade Packb has been numerically investigated under unsteady condition. The results of the numerical simulation are confirmed by the experimental findings. The simulations are performed with the CFX software, and the LES with Smagorinsky subgrid scale model is used to analyze the changes on the endwall flow induced by the wake. The study shows that the presence of wake will cause periodic changes in the secondary flow strength at the exit of the cascade. The alternating excitation and suppression effects are caused by the different positions of the wakes in the passage. The periodic suppression effect of wake can be used to effectively reduce the flow loss in the turbine endwall region.