涡轮叶尖迷宫式密封对泄漏流场影响的数值模拟

采用基于密度修正的三维计算流体力学程序,结合雷诺应力湍流模型加壁面函数的方法,对某一轴流涡轮转子叶尖迷宫式密封对泄漏流场的影响进行了数值研究,分析了全叶冠密封和部分叶冠密封中的泄漏流场,并详细研究了迷宫密封采用的锯齿状肋条数目对密封效果的影响,最后计算了转子效率。结果表明:涡轮叶尖表面加叶冠对进行密封,可以显著提高涡轮效率,全叶冠密封下涡轮效率提高1.15301%,部分叶冠密封涡轮效率增加0.54713%;迷宫密封中锯齿状肋条数有一个最佳值,且在此锯齿状肋条数下进行迷宫密封涡轮效率相对无锯齿状肋条增加0.1%。

Numerical simulation of labyrinth seal on tip leakage flow in partially and fully shrouded axial turbine

A density-correction based,3D Reynolds-averaged Navier-Stokes equations CFD code with Reynolds stress model and wall function was used to simulate the effects of labyrinth seal on the tip leakage flow in a turbine rotor.The tip leakage flow in partially and fully shrouded axial turbine is analyzed and the effect of the saw tooth rib number on the sealing performance is studied in details.The turbine efficiency is calculated.The results show that the tip shroud can significantly increase the turbine efficiency.The efficiency can increase by 1.15301% in fully shrouded turbine,and so does it by 0.54713% in partially shrouded turbine.There is an optimal sawtooth rib value in the labyrinth seal.Compared with non-sawtooth rib,the turbine efficiency in this labyrinth seal can increase by 0.1%.