EXPERIMENTAL STUDY ON NONLINEAR DYNAMICS CHARACTERISTICS OF HIGH-SPEED ROTOR-GAS LUBRICATION BEARING SYSTEM

An experimental study was done with the nonlinear dynamics characteristics of high-speed rotor-gas lubrication bearing system analyzed using the orbits of shaft center, 3D frequency coupling diagram, frequency spectrum and bifurcation diagram. Experimental results indicate that gas whirl is the main cause for the nonlinear instability of the high-speed rotor-gas lubrication bearing system, and the double periodic bifurcation resulting from gas whirl leads to the chaos vibration of the rotor-bearing system. It is therefore concluded that it is a new way to improve the nonlinear stability of a rotor-bearing system to keep the instability rotation speed far away from the design rotation speed by modulating the coupling between the natural frequency of the system and the gas whirl frequency, and to use the boundary nature of chaos verified through experiments to control the amplitude of vibration.