气体润滑轴承-转子系统非线性动力学特征的实验

Experimental research on nonlinear dynamic characteristic of gas lubrication bearings and high speed rotors

对高速气体润滑轴承转子系统进行了稳定性试验研究.通过轴心轨迹、频率耦合三维图、频谱和分叉图,分析了系统非线性行为特征.实验证明气体润滑轴承-转子系统中的气膜涡动是系统非线性失稳的主要原因,气膜涡动导致的倍周期分叉是系统进入混沌振动的必由途径.通过调整系统固有频率和气膜润滑涡动频率之间的耦合关系,使得失稳转速远离设计转速;以及利用试验中所证实的混沌"有界"性质,有效的控制振幅,将是提高转子-轴承系统非线性稳定性的新途径.

A stability experiment on high speed rotor and gas lubrication bearings was presented in this paper. Based on shaft center orbits, frequency coupling 3-D plot, frequency spectrum and bifurcation plot, the nonlinear characteristics of rotor bearing system were analyzed. The experiment proved that, gas whirl in gas bearing and rotor system was a major contributing factor to nonlinear instability. Double periodic bifurcation caused by gas whirl was an inevitable path to chaos vibration. The instability rotational speed will vary a lot from design speed by modulation of the coupling relationship between system＇s inherent frequency and gas whirl frequency, meanwhile effective control of chaos vibration based on bounded ness of chaos is a new method to improve nonlinear stability of rotor and bearings.