Research On Micro-textured Gas Foil Bearing Characteristics Based On Multigrid Method

Gas foil bearings use air as a lubricant,which have the advantages of high speed,high precision,cold resistance,low friction,no pollution and long service life,and are used more and more in the aerospace field.In this paper,the bearing-rotor system of a certain type of aircraft environmental control device is taken as the research object,and the influencing factors of the static and dynamic characteristics of the multi-leaf radial gas foil bearing and the superimposed thrust gas foil bearing are studied.At the same time,the surface micro-texture technology is applied to the inner surface of the radial bearing to study the variation law of bearing static characteristics caused by micro-texture,which lays a foundation for bearing optimization and improvement work in the future.Due to the small size of the micro-texture,a large number of meshes are needed to more realistically simulate the change of bearing performance caused by micro-texture,and the multi-grid method has a fast and stable solution to the problem of calculating the number of meshes in the domain.The numerical simulation of the static and dynamic characteristics of the foil bearings by writing multi-grid method program can get better simulation results.For the multi-leaf radial gas foil bearing,the pressure control equation suitable for radial gas bearing is derived by simplifying the momentum equation and the continuity equation,the discretization form and numerical solution method of the pressure control equation are given by the central difference method;T he calculation of gas film thickness is introduced in detail through geometric analysis and the method of establishing one-dimensional beam model stiffness matrix.The influence factors of static and dynamic characteristics such as pressure distribution,film thickness distribution,bearing load capacity and stiffness damping coefficients of multi-leaf radial gas foil bearing are analyzed.For the superimposed thrust gas foil bearing,the pressure governing equations applicable to the thrust gas bearing are derived by simplifying the momentum equation and the continuity equation in the cylindrical coordinate system,and the discretization form of the pressure control equation is given by the central difference method;The calculation of the film thickness is introduced in detail through the contact analysis and the method of establishing the stiffness matrix of the two-dimensional flat model.The influence factors of static and dynamic character-ristics such as pressure distribution,film thickness distribution,bearing load capacity and stiffness damping coefficients of superimposed thrust gas foil bearing are analyzed.In this paper,the cylindrical surface micro-texture is applied to the inner surface of multi-leaf radial gas foil bearing,and the influence of micro-texture on the static characteristics of the foil bearing under the rigid surface is analyzed.The influence of different texture numbers,different texture radius and different texture depths on the static parameters of foil bearings was studied.