油叶型轴承—不平衡转子系统的非线性动力学分析

基于变分法提出了一个求解雷诺边界条件下有限长轴承油膜力的快速算法,用此算法对一个三油叶不平衡轴承—转子系统的非线性动力学行为进行了一系列的分析。数值模拟的结果显示了转子由稳定的同步涡动分岔为半频油膜涡动继而变为油膜振荡的失稳过程,还分析了轴承形状、轴承间隙、转子的质量大小、质量偏心位置等参数对转子运动的影响,提出了如何通过调节这些参数来提高转子系统稳定性的方法。

Nonlinear Dynamic Behaviors of an Imbalance Rotor on Multi-Lobe Bearings

Based on the free boundary theory and the variational method,a fast and accurate model for the calculation of the fluid-film forces under the Renolds boundary condition is presented.The model has been applied to the nonlinear dynamic behavior analysis of an imbalanced rigid rotor with two three-lobe bearing supports.Numerical simulation shows that the imbalanced rotor undergoes a bifurcation from synchronous motion to double period motion and at last loses its stability as chaotic motion. This paper also studied the influences of the rotor mass and the mass eccentricity. It is found that the threshold speed at which the rotor will lose stability decreases with the increase of rotor mass.The eccentricity influences the motion of the rotor seriously.The rotor threshold speed increases rapidly with the increase of mass eccentricity.Study of the elliptical bearing shows that the threshold speed of rotor supported by three-lobe bearings is higher than that of the elliptical bearings.