Research Of Influence Of Cylindrical Global Sizes Based Film Thickness On The Performance Of Aerostatic Bearing

Based on Fluent and Samcef softwares,the performance of the aerostatic bearing was studied through simulation.The bearing capacity and stiffness of the aerostatic spindles with the different geometrical errors and the porous aerostatic bearings were analyzed by using Fluent software based on the finite volume method,and the stiffness of the aerostatic spindles with the different global sizes corresponding to the geometrical errors above were determined by using empirical formula.The analysis results showed that owing to that the gas film thickness variation caused by geometrical errors make the pressure uneven,when geometrical errors with convex-straightline,convex-arc and taper were controled within 3?m,they have an increase on the stiffness of the spindle and bearing above.The stiffness values of the aerostatic spindle with geometrical errors and global sizes were compared.For three global sizes,the stiffness of the aerostatic spindle with least-squares size is more suitable.Based on the stiffness analysis of the aerostatic spindle above,the system of the porous aerostatic bearing-rotor was established by using Samcef software,and its rotary accuracy was analyzed.Through processing the simulation results,the rotary orbits of the spindles were obtained and displayed by using Matlab.The analysis results of the rotary accuracies of the aerostatic spindle based on geometric errors above were compared with the results of the aerostatic spindles based on global sizes above.The analysis results showed that it is more suitable that the rotary accuracy is evaluated based on the film thickness formed by the least-squares sizes of the spindle and bearing.The measurement experiment for the rotary orbit and stiffness of aerostatic spindle was done.The project may has important practical value for improving the design and manufacturing of ultra aerostatic bearing spindles.