超高速转子系统动力学特性(I):无碰摩转子

Research on Dynamic Characteristics for a Super-High Speed Rotor System (I):Rotor System Without Rubs

关键词:  超高速  转子系统  振动  碰摩  动力学  分岔  混沌

Key words:  Super-high speed  Rotor system  Vibration  Rub  Dynamics  Bifurcation  Chaos

摘要:

为排查超高速转子系统碰摩故障原因,利用混沌、分岔理论,研究了无碰摩转子系统的动力学特性。以实际转子结构为对象:建立物理模型；由拉格朗日(Lagrange)法建立系统动力学方程；用四阶龙格库塔(Runge-Kutta)法数值求解方程；结合分岔图、轴心轨迹、相图、Poincare映射等手段,分析了无故障转子系统的动力学行为及系统参数变化对其动力特性的影响。结果表明:该转子系统动力学状态过渡过程不明显,在全转速域内,振动以高频低幅为主,高速时具有良好的动力稳定性；扭振特征不明显；质量盘之间的动力耦合效应较弱,有利于系统稳定性；对于单个质量盘,弯振和摆振具有同步性和耦合性,横向振动和扭振动力耦合效应较弱。研究结果说明,该转子结构在冷态条件下,不致在高速状态下引起混沌运动状态。

Abstract:

To check the reason that rotor rubbed with stator, the dynamic characteristics of a super-high speed rotor system without rubs were studied based on theory of dynamic system chaos and bifurcation. Physical model was built according to the prototype of the rotor, dynamics equations for the system were deduced by Lagrange method and solved numerically by 4th Runge-Kutaa method. By combining ways of bifurcation chart, shaft orbit, phase diagram and Poincare map, contents are studied including dynamic features and effects that changes of system parameters act on the rotor system. The results show that the rotor system has the ability to transfer into different dynamic behaviors quickly. Its vibration presents low amplitude with high frequency in whole work domain and its dynamic stability is good under high speed. Torsional-vibration is unconspicuous and dynamic coupling effect between different discs is so weak that it is helpful to system stability. For single disc, bending vibration and pendulum vibration are synchronous and coupling, and lateral vibration and torsional vibration are weakly coupled with each other. All those tend to show that the rotor system will not change into chaos at high speed when it works under natural condition. These contents are helpful for pointing out the direction to check fault reason. 