高维转子-轴承系统非线性动力稳定性分析

Nonlinear dynamic stability analysis for a large-scale rotorbearing system

采用基于固定界面模态综合法的降维方法对大型实际非线性转子-轴承系统稳定性进行了分析.对降维前后的200 MW汽轮机低压转子-轴承系统采用Newm ark法进行了数值计算,结果表明:该降维方法能较完整地保留系统的振动特性,显著提高计算和分析的效率.利用该方法对短圆柱瓦轴承支撑下转子稳定性随转子不平衡量、轴承长径比、润滑油粘度、间隙比的变化规律进行了计算,所得结果为实际非线性转子-轴承系统非线性动力稳定性设计和运行提供了理论指导.

A reduction calculation method based on fixed interface component mode synthesis is applied to analyze nonlinear dynamic stability of an actual large-scale rotor-beating system. The reduced motion equations of a 200 MW steam turbine low-pressure rotor bearing and that without reduction are calculated numerically using the Newmark method. The comparison results show that the reduction calculation method can simulate the vibration characteristics of the system very well and remarkably improve the efficiency of calculation. The changing rule of stability of the rotor with eccentricity of the rotor, the clearance-to-radius ratio, the length-to- diameter ratio, and oil viscosity of the bearing is revealed by numerical calculation. The results provide the theoretical basis for analyzing stability in the design and operation processes of this type rotor-bearing system.