涡轮叶尖镶嵌肋条对泄漏流场的影响

Influence of squealer tip on tip leakage flow in axial turbine

结合基于压力修正的采用雷诺应力湍流模型加壁面函数的三维计算流体力学程序,通过沿着叶尖表面加肋条以期减小叶尖间隙泄漏损失,对某一轴流涡轮转子叶尖表面镶嵌肋条对泄漏流场细节的影响进行了数值研究,并详细分析了不同肋条高度和肋条宽度对泄漏流场的影响.结果表明:肋条使得气流通过压力面肋条时出现分离形成回流区,阻碍泄漏流动,减小泄漏损失;肋条高度h对涡轮效率有较大影响,且有个最佳肋条高度值,在最佳肋条高度下涡轮效率提高0.13%;肋条宽度w对流场影响不大,但小肋条宽度形成较大的空腔,可以稍提高涡轮效率.

In order to reduce the tip leakage loss, a pressure-correction based, 3-D Reynolds-averaged Navier-Stokes equations CFD code with Reynolds stress model and wall function was used to simulate the effects of the passive control of a partial squealer tip around tip platform on the tip leakage flow in a turbine rotor. The effect of squealer tip with different rim heights and widths on the tip leakage flow was sequentially simulated. The results show that recirculation region appeared in the tip region and the rim near suction side could block the tip leakage flow, which decrease the tip leakage loss. The height of tip platform rim had more influence on the turbine effficiency, and it had an optimal value, where the turbine efficiency could increase by 0. 13 percent. The rim width had less influnce on the flow field, but it made the cavum became large, so the turbine efficiency slightly increased.