复杂转子-轴承-汽封耦合系统的非线性振动分析

基于非线性动力学和转子动力学理论，综合考虑Muszynska非线性汽封力、非线性油膜力和转子不平衡量的耦合作用，建立了双叶轮-轴承交错布置的复杂转子-轴承-汽封系统动力学模型。采用有限元法（FEM）推导系统运动微分方程，编程计算了系统转速、圆盘偏心量、汽封长度和汽封间隙等参数对系统动力特性的影响，并利用分岔图、频谱图、相轨迹和Poincare映射图表征了系统的运动性态。研究表明：耦合系统具有高度非线性，随着参数的变化系统呈现出周期运动、倍周期运动、准周期运动和混沌运动等复杂动力学行为。通过减小圆盘偏心，增加系统汽封长度，选取合适的汽封间隙有利于提高转子-轴承-汽封系统的稳定性，改善系统的运动特性。

Vibration analysis of a nonlinear rotor-bearing-seal system

Based on the theory of nonlinear dynamics and rotor dynamics, a new complicated rotor-bearing-seal system of double impeller-bearing staggered arrangement model, coupling the Muszynska’s nonlinear seal force, the nonlinear oil film force and the mass eccentricity of the disk, is proposed. The finite element method(FEM) is applied to derive the motion differential equation of system and programming analysis the effects of system speed, disk eccentricity, seal length and seal clearance on the dynamic characteristics of the system. By using the bifurcation diagrams, frequency spectrums, phase trajectory maps, Poincare maps, the dynamic state of the system is represented. The studies demonstrate that coupling system is highly nonlinear; with parameters change the system exhibits rich forms of dynamic behaviors including periodic, multi-periodic, quasi-periodic and chaotic motion. Small disk eccentricity, long seal length and suitable seal clearance is beneficial to improve the stability of the system.