Research On Fluid-solid Coupling Characteristics And Experiment Of Gas Bearing-rotor System

The gas bearing-rotor system has the advantage of high precision,high speed,low wear,long life and smooth operation.Due to the compressibility of the gas,there is a strong coupling between the gas bearing flow field and the rotor.In order to improve the comprehensive performance of the machine,it is necessary to fully consider the coupling between the gas bearing flow field and the rotor at different working conditions in the design and development stage.And put forward more perfect design criteria,which is important for the design and development of precision and ultra-precision machine.The gas bearing is taken as the research object.The pressure distribution of flow field,bearing capacity,stiffness of gas bearing,attitude angle at different working condition are analyzed.The results show that the change of rotor speed and eccentricity will cause the change of viscous flow,differential pressure and compressibility of gas.Then the strength of dynamic and static coupling effects is changed,and the pressure distribution of flow field in circumferential direction is uniformity.At the same eccentricity rate,the bearing capacity and stiffness increase with the increase of the rotating speed,and the attitude angle first increases and then decreases.When the rotor speed is kept within certain lower speed,the attitude angle increases with the increases of the eccentricity,the trend at higher speed is opposite.The characteristic of gas bearing-rotor system at inclined condition is researched with fluid-solid coupling.The bearing capacity,the dip angle of rotor axis and eccentric angle of gas bearing-rotor system at different radial loading and rotating speed conditions are analyzed.The results show that the dip angle of rotor axis increase monotonously with the increasing eccentricity rate under the same conditions of rotor speeds and gas supply pressure.The dip angle of rotor axis and the eccentricity ratio decrease with the increasing of rotor speeds,and the eccentric angle increase under the same gas supply pressure and loading force.Compared to the ideal state,the dip of rotor axis lead to decline of safe eccentricity rate of gas bearing,bearing capacity and stiffness of gas bearing.Experiment rig of gas bearing-rotor system is established,and load test of gas bearing-rotor system is used non-contact loading.The results of tests show that variation of the dip angle,clearance of flow field and bearing capacity at different working conditions are consistent with the trend of simulation.