升降速过程中转子系统油膜失稳规律

以某悬臂转子-轴承系统为研究对象,基于有限元方法建立了转子-轴承系统动力学模型。通过时域图、三维谱图和幅频响应图得到了转子系统升降速过程中出现的油膜失稳特征,分析了不同角加速度值在升降速过程中对1阶和2阶油膜失稳规律的影响。研究发现:升降速过程中产生的切向惯性力会改变油膜失稳转速,与稳态情况(角加速度为零)相比,升降速情况下2阶油膜失稳转速有所延迟;升速过程中随着角加速度值的增大2阶油膜失稳转速略有增加、降速过程略有减小;降速过程与升速过程相比,出现明显的迟滞效应。

Research on Oil-Film Instability Law of a Rotor Systemduring Run-Up and Run-Down Processes

The finite element model (FEM) of an overhung rotor-bearing system is established. Oil-film instability features and the effect of angular accelerations on oil-film instability laws are analyzed during run-up and run-down processes by the time-domain waveform, spectrum cascade and amplitude-frequency response. The results show that the onset of oil-film instability changes due to the tangential inertia force from run-up and run-down processes, and the instability speeds under the run-up and run-down conditions will be delayed compared with that under stable conditions (with no angular acceleration). Moreover, the second mode instability speed increases slightly as angular acceleration increases in run-up conditions, and decreases slightly in run-down conditions. The phenomenon of hysteresis under run-down conditions can be observed compared with the run-up condition.