高低式迷宫密封转子动特性的数值模拟及优化

Numerical Investigation and Optimization for the Rotordynamic Characteristics of a Staggered Labyrinth Seal

本文建立涡动转子-迷宫密封三维CFD模型,计算高低式迷宫密封流场及流体激振力,并计算密封转子动特性,计算结果经Pugachev试验数据验证可靠。分析不同结构的高低式迷宫密封转子动力学特征,尤其是广泛应用于汽轮机高压级围带密封的前后凸台高低式迷宫密封结构。结果显示,在高低式迷宫密封中,凸台位置越靠后,主阻尼系数越小;对于前后凸台的高低式迷宫密封结构,去掉后凸台能提高转子稳定性。

A 3D CFD model of seal-whirling rotor was established to simulate flows in the stag- gered labyrinth seal cavities, as well to calculate seal forces and rotordynamic characteristics. The predictions were in good agreement with experimental data published by Pugachev. Different types of staggered labyrinth seal were studied, especially the one who had two stages, which was widely used in the high pressure cylinder shroud seals of steam turbine. The result showed that in staggered labyrinth seals, a more rearward position of the stage would lead to a decrease in direct damping coefficient. The rotordynamic performance of a two stage staggered labyrinth seal would be better if the latter stage was removed.