迷宫密封激振力作用下转子系统非线性动力学分析

Nonlinear dynamic analysis of a rotor system excited by labyrinth seal force

由双控体模型确定迷宫密封轴向平均流速,结合Muszynska气流激振力建立了转子-密封系统非线性动力学模型,并采用Runge-Kutta-Fehlbrg方法求解系统非线性动力学方程。分析了迷宫密封间隙、密封半径、齿数、齿腔宽度、进口气压等参数对泄漏量及轴向平均流速的影响;绘制了分岔图、轴心轨迹、Poincare图和频谱图等,研究了转速、进口气压、偏心距及密封有效总长度对系统动力学特性的影响。数值结果表明,转速、密封结构及介质参数的改变能够诱导系统发生单周期运动、概周期运动等复杂的非线性动力学行为。

Here,the nonlinear dynamic model of a labyrinth seal-rotor system was built using Muszynska＇s nonlinear seal forces.In the process of nonlinear dynamic analysis,the axial mean flow velocity of the labyrinth seal was determined with the two-control-volume model.Applying Runge-Kutta-Fehlbrg numerical integration,the nonlinear dynamic equation of the system was solved.The effects of parameters,such as,labyrinth seal clearance,seal-radius, number of seal strips,cavity-width and inlet air pressure on leakage and axial mean flow velocity were analyzed.The influences of rotational speed,inlet air pressure,eccentricity and effective seal-length on the nonlinear dynamic characteristics of the system were also studied.The nonlinear dynamic properties of the system were described with bifurcation diagrams,axis orbits,Poincare Maps and frequency spectra.The numerical results showed that the changing of rotating speed,seal geometry and seal medium parameters can induce abundant nonlinear dynamical behaviors like periodic motion and quasi-periodic motion,etc.