Analysis Of Dynamic Behavior Of Journal Bearing-rotor System

The rotating machines are developing toward high speed and precision,and the dynamic characteristics of bearing-rotor system have been paid more and more attention because the bearing-rotor system is a key component of the rotating machines.This study focus on the journal bearing-rotor system,and the solving method of nonlinear oil film force of the bearing and the dynamic response of the rotor are investigated.The main contents are listed as follows:1.For the finite journal bearing,the finite difference method and the approximate analytical method are used to calculate the hydrodynamic Reynolds equation for the nonlinear oil film force.And then,the nonlinear oil film force of the bearing is analyzed for various deviation angles and eccentricity ratios.2.For the rigid rotor system supported by journal bearing,the dynamical model of the system is developed with consideration of the asymmetrical rotor.The Newmark method is adopted to solve the dynamical model,and the bifurcation diagram is used to analyze the unbalanced responses of the journal bearing-rigid rotor system with the changing of eccentricity ratio and rotor speed.3.By considering the effects of rotor inertia,shear deformation,gyro effect,and axial torque caused by power transmission on the vibration of the rotor,the vibration differential equation of the journal bearing-flexible rotor system is developed.On this basis,the unbalanced responses of the rotor are analyzed with the changing of rotor speed,and the influence of the axial torque on the rotor dynamic response is also investigated.4.The modal and transient dynamics of the journal bearing-crankshaft system are analyzed by using the finite element method.The natural frequency of the journal bearing-crankshaft system and its vibration-type cloud diagram are obtained.On this basis,the maximum transient deformation is investigated with the changing of the time.The above research provides a theoretical basis for the stability analysis and dynamical design of the bearing-rotor system.