摘 要：高低齿迷宫密封是透平机械中抑制流体泄漏的关键部件。以某机组隔板密封为对象建立高低齿迷宫的计算流体力学（CFD）模型，研究由变工况引起的转子轴向偏移对密封泄漏特性的影响，并通过调整转子凸台宽度和密封腔高度对密封结构进行优化。结果表明：原始结构设计下，转子轴向偏移±3 mm内，泄漏量并未发生大幅度的上升；在-2~1.5 mm范围内泄漏量有所下降，说明在工况变动不大时，密封性能有所提高，但超出±3 mm的范围，泄漏量呈突增趋势；泄漏量分别随转子凸台宽度和密封腔高度呈二次非线性变化，存在一个最佳值使泄漏量达到最小，最佳凸台宽度和密封腔高度分别为5.13和7.5 mm；结构优化后密封泄漏量在正常工况及变工况下均小于原始结构，密封性能得到提高。

Abstract:Staggered labyrinth seal is a key component to suppress fluid leakage in turbine machinery.In this paper,CFD model of a staggered labyrinth seal is established.Influence of the rotor axial shifting caused by the off-design condition on the leakage characteristics is studied.The seal structure is optimized by adjusting the width of rotor convex plate and the height of seal cavity.Calculated results show that:(1) the leakage flow rate has no evident change in the axial shifting range of ± 3 mm,while it shows a decreasing trend in the axial shifting range of -2 mm~+1.5 mm.This indicates that it can improve the sealing performance when working conditions change within a certain range.The leakage flow rate,however,shows a dramatic increase as the axial shifting beyond the range of ±3 mm.(2) The leakage flow rate shows a quadratic nonlinear change with the rotor convex plate width and seal cavity height.There is an optimal value to minimize the leakage,with rotor convex plate width and seal cavity height of 5.13 mm and 7.5 mm,respectively.(3) The leakage flow rate of the optimized structure is smaller than that of the original structure under the normal and off-design working conditions,indicating the improvement in the sealing performance.

TB42

国家自然科学基金（11402148，51676131）