Hydrodynamic Lubrication of Elastic Foil Gas Bearing Using Over Relaxation Iteration Method and Non-Dimensional Equation

Abstract

The purpose is to accurately predict the performance of foil bearing and achieve accurate results in the design of foil bearing structure. A new type of foil bearing with surface microstructure is used as experimental material. First, the lubrication mechanism of elastic foil gas bearing is analyzed. Then, the numerical solution process of the static bearing capacity and friction torque is analyzed, including the discretization of the governing equation of rarefied gas pressure based on the non-dimensional modified Reynolds equation and the over relaxation iteration method, the grid planning within the calculation range, the static solution of boundary parameters and static solution of the numerical process. Finally, the solution program is analyzed. The experimental data in National Aeronautics and Space Administration (NASA) public literature are compared with the simulation results of this exploration, so as to judge the accuracy of the calculation process. The results show that under the same static load, the difference between the minimum film thickness calculated and the test results is not obvious; when the rotor speed of the bearing is 60000 r/min, the influence of the boundary slip effect increases with the increase of the micro groove depth on the flat foil surface; when the eccentricity or the micro groove depth of the bearing increases, the bearing capacity will be strengthened. When the eccentricity is 6 µm and 14 µm, the viscous friction torque of the new foil bearing increases significantly with the increase of the depth of the foil micro groove, but when the eccentricity is 22 µm, the viscous friction torque does not change with the change of the depth of the foil micro groove. It shows that the bearing capacity and performance of foil bearing are improved.