Investigation On Vibration Stability Of Tilting Pad Bearing-rotor System

Tilting pad journal bearing has been used in various rotary machine.The movement state and behavior of bearing plays a key role in the operation stability of the rotor.More attention should be payed to study the effects of the bearing and rotor parameters on the behavior of rotor system,which will give a reference for the tilting bear design and fault diagnosis of rotor system.Based on the well-known unsteady Reynolds equation,simplified one-dimensional Reynolds equation was obtained by taking the assumption of parabolic pressure.Considering the swing angle of pad and the structural parameters,the finite difference method and the Reynolds boundary condition was applied to calculate the oil film pressure distribution of pads.With the pastures of pads being taken into consider,the Euler method is used to solve the trajectory of the shaft center and to analyze the influence of the speed of the shaft,clearance and numbers of the pads.The results show that,the vibration amplitude of the shaft center and the film pressure varies inherently with different conditions.The critical speed of the shaft increases with the decrease of the clearance and the increases of the numbers of pads.But the maximum displacement also increases with the increases of the numbers of pads.So,in engineering design the balance should be find in order to meet the requirements of high speed and high stability of tilting pad journal bearings.Finally,the critical speed and unbalanced response of the bearing-rotor system of a centrifugal compressor has been analyzed by lumped model with Riccati transporting matrix method.Meanwhile,the influence rules of different support parameters on the critical speed is described,which provides helps for structural optimization.