Analysis of Excitation Response of Gas Bearing - rotor System with Fluid-structure Coupling Method

The precision of the spindle plays an important role in practical machining. The gas bearing-rotor system is an important part, and its performance directly affects the machining precision. There is a strong coupling effect between the gas film flow field in the gas-bearing rotor system and the rotor movement under transient load. To study the influence of excitation load on the transient response characteristics of gas bearing-rotor system, a method combining fluid-structure coupling simulation and experiment was adopted to study the rotor migration, axis center trajectory, and flow field characteristic distribution of gas bearing-rotor system under sinusoidal excitation loading. The results show that with the increase of the excitation frequency of the external load, the position migration of the lower end of the rotor presents a non-monotonic change rule, and there is a phase lag between the rotor and the external load. When the excitation frequency is less than 300Hz, the rotor migration increases with the increase of rotational speed. When the excitation frequency exceeds 400Hz, the rotor migration decreases with the increase of rotational speed. The phase difference between rotor migration and external load increases with the increase of excitation frequency and speed. The high-speed rotation of the rotor brings the asymmetry of the pressure distribution in the flow field. The higher the rotational speed, the more obvious the asymmetry of the characteristic distribution of the flow field.