百万kW水轮发电机组主轴密封浮动环浮动量计算及分析

Calculation and Analysis of the Floating Amount of the Floating Ring of the Main Shaft Seal in Million-kW Hydro-turbine Generator Units

白鹤滩水电站共有16台百万kW立轴混流式水轮发电机组,其主轴密封为静压自平衡式轴向密封结构,结合其水文条件,由流体力学不可压缩粘性流体层流运动的诺维一斯托克斯方程,对浮动环的工作原理建立数学模型,求出给水压力与浮动量、流量等参数的表达式。然后结合水轮发电机组尾水位和主轴密封结构尺寸等,可得到在任一尾水位时的主轴密封给水压力与浮动量的函数变化关系,即可求出给水压力的调整范围,为机组主轴密封运行参数的选取、相关缺陷的分析诊断和优化主轴密封运行工况提供重要的数据参考。

There are 16 vertical shaft Francis hydro-turbine generator units with million-kW capacity in Baihetan Hydropower Station.The main shaft seal of these units is of a hydro-static self-balancing axial seal structure.Considering the hydrological conditions of the station,a mathematical model is established following the working principles of the floating ring based on the Navier-Stokes equation for incompressible viscous fluid laminar flow in fluid mechanics,and the expressions of the feed water pressure with parameters such as the floating amount and the flow rate are obtained.Then,based on the tail water level and the dimensions of the main shaft seal structure of the units,the relationship functions between the main shaft seal feed water pressure and the floating amount at any tail water level can be determined.The adjustment range of the feed water pressure is thus obtained,which provides important reference data for the selection of operational parameters,defect analysis and diagnosis,and optimization of the operation conditions of the main shaft seal.