偏心量对转子-轴承-密封耦合系统非线性振动特性影响的分析

转子偏心量是直接关系转子系统运行稳定性的一个重要因素,将迷宫密封力模型和capone圆轴承非线性油膜力模型相结合,建立了具有非线性转子-轴承-密封耦合系统的动力学模型,研究了转子-轴承-密封耦合系统在不同的偏心量下的非线性动力学行为。针对转速对耦合系统动态响应进行了仿真计算,给出了四个不同转子偏心量下系统轴颈和圆盘随转速变化的响应分叉图,以及典型转速下的Poincare截面图。研究发现随着不平衡量增加,系统出现了混沌运动,但在较大不平衡量时,随着转速的增加,系统在混沌运动后最终呈现同频周期运动,这表明较大的不平衡量反而有助于增加系统稳定的作用。还给出了系统在特定转速下偏心量变化影响下的分岔图,并分析了变化的平衡量下系统对应着复杂的非线性运动。数值计算表明,转子转速、偏心量都是影响系统动力学行为的重要因素,随着转速和偏心量的变化,系统呈现单周期运动、拟周期运动、混沌运动等复杂的动力学行为,具有很强的非线性特征。并且这些结果为实验中偏心量的选择提供了有利的依据。

Nonlinear dynamic analysis for unbalanced rotor-bearing-seal systems

Rotor eccentricity is one of the most important factors which is directly related to the rotor system stability.The dynamic model of nonlinear rotor-bearing-seal system was set up in this paper,combining the nonlinear Muszynska seal forces and Capone bearing forces models.The nonlinear dynamics behaviour of unbalanced rotor-bearing-seal coupled systems under different eccentricities were studied.Through the simulation of the dynamic response of the coupled system with the changes of speed,Bifurcation diagrams and Poincare maps were given in four different rotor eccentricities.With the eccentricity increasing,system has got chaotic motion,but in larger unbalance,it shows the same frequency periodic motion finally,suggesting that the larger unbalance help increase the system stability.Bifurcation diagrams of the response to the changing of rotation speeds were also given.The computational results show that the rotor speed,eccentricity are important factors of the coupled system dynamic behaviour,the system presents a periodic,quasi-periodic motion,chaos motion and abundant nonlinear dynamical behaviour with the changes of the speed and eccentricity.