Hydrodynamic Analysis of Journal Bearings Considering Anisotropic Slip and Elastic Deformation

Abstract

An anisotropic slip boundary condition which will change the lubrication behavior of the surface is one of the factors that cannot be ignored at the microscopic scale Considering the rigid body the elastic deformation of the material is also an important factor that affects the distribution of the film thickness In this study the lubrication theory with anisotropic slip boundary conditions and elastic deformation is proposed The traditional Reynolds equation is modified using Navier slip boundary conditions with orthogonal slip length and flow factor method Additionally elastic deformation is considered in the film thickness equation The finite element method (FEM) is used to solve the hydrodynamic problem of journal bearings in asteady state We can get the bearing performances (eccentricity ratio film thickness distribution film pressure distribution elastic deformation attitude angle friction torque coefficient of friction cavitation area and flow rate correctors) under the different variables (load and slip length) The difference from the traditional models of the journal bearing hydrodynamic problem is that this study is solving the eccentricity ratio and attitude angle for a given load and load direction In addition this study has done coordinate transformation to cooperate with the real working environment The final result shows that considering the elastic deformation the eccentricity ratio will increase the film thickness will increase and the cavitation zone will reduce Considering the anisotropic slip boundary condition the eccentricity ratio will increase Slip in the x direction causes a reduction in the friction torque; slip in the y direction causes an increase in the friction torque Slip in the x direction will reduce the elastic deformation; slip in the y direction will increase the elastic deformation

Date of Award	2019
Original language	English
Supervisor	Wang-Long Li (Supervisor)