水轮机迷宫密封系统非线性动力稳定性研究  

Study of nonlinear dynamic stability of labyrinth seal-rotating wheel system in hydraulic turbines

作　　者：杨晓明[1] 马震岳[1] 张振国[2] 

机构地区：[1]大连理工大学土木水利学院,辽宁大连116024 [2]内蒙古工业大学,内蒙古呼和浩特010051

出　　处：《大连理工大学学报》2007年第1期95-100,共6页Journal of Dalian University of Technology

基　　金：高等学校博士学科点专项科研基金资助项目(20030141018)

摘　　要：采用M uszynska非线性密封力模型,分析水轮机转轮密封系统非线性动力学特性,研究迷宫密封对水轮机转轮系统动力稳定性的影响.受密封力作用转轮发生自激振动,当转轮达到一定转速后开始失稳,发生Hop f分岔,进入周期涡动状态,涡动幅度随转速的提高而增大,增大到一定程度后,密封和转轮发生碰摩.根据Lyapunov第一近似理论判断非线性系统的运动稳定性,采用R unge-K u tta法数值模拟了转轮的轴心轨迹.通过改变迷宫密封的物理和结构参数,对系统运动特性进行敏感性分析,将M uszynska模型与八参数模型进行比较证明其变化趋势相同.The Muszynska＇s model of seal fluid dynamic forces is used to analyze the nonlinear dynamic characteristics of labyrinth seal-rotating wheel system in hydraulic turbines, and investigate the nonlinear dynamic stability of hydraulic turbines with labyrinth seal. The results show that there is occurrence of Hopf bifurcation after threshold speed is exceeded and the rotating wheel comes into bifurcated periodic orbit. While the amplitude of bifurcated motion will rise according to improvement of rotor speed, which may cause the rotating wheel impact seal at certain speed. Lyapunov＇s first approximate theory is used to analyze nonlinear system stability, and Runge-Kutta method is used to analyze numerical simulation computation. Finally, the influence of physical and structural parameter of seal on rotor is investigated. Sensitivity analysis of nonlinear dynamic characteristics is performed by changing the physical and structural parameters of seal-rotating wheel system. By comparing with eight-parameters model, it is tested that the variation tendency of Muszynska model is identical.

关 键 词：自激振动 转轮密封 失稳转速 稳定性 Runge—Kutta Lyapunov近似理论 

分 类 号：TV312[水利工程—水工结构工程]