Study On Flow Field Characteristics And Ripple Error Effect Of Aerostatic Radial Bearings

With the progress of the society and the continuous renewal of science and technology,the whole manufacturing industry and the equipment industry have a higher and more extensive demand and demand.With a high rotational speed,the rotating machinery with small friction coefficient is very important to the manufacturing industry,and the gas bearing is a high speed,high precision,non polluting bearing rotor.The aerostatic radial bearing is a high speed rotating machine with compressed air as the lubricating medium.The compressed air is suspended in the bearing by the compressed air,thus the separation between the rotor and the stator is realized.At present,there are some problems in the actual application of the whole gas bearing,so it is still necessary to be static.The performance of radial pressure gas bearings is constantly understood,providing a theoretical basis for manufacturing and use.In this paper,the static pressure gas bearing of high speed static pressure is used as the research object.Through the establishment of a small hole throttle static pressure gas bearing model,the compressible Reynolds lubrication equation containing the throttle mass is solved,and the static characteristics of the static pressure bearing are studied by the combination of the difference method and the Newton iteration to study the static characteristics of the static pressure bearing.The stability of the bearing can not be judged.In this paper,the model is calculated by setting up the perturbation method,and the trigonometric function of the disturbance complex function is changed.The vibration amplitude and frequency of the bearing are linearly processed to calculate the dynamic change parameters of the gas bearing.At the same time,the error of manufacturing in the manufacturing process is no longer.In this paper,the static and dynamic characteristics of the ripple manufacturing error in the gas bearing are analyzed by establishing the mathematical trigonometric function expression on the basis of considering the ripple error in the error.Through the analysis of static characteristics of static pressure gas bearing,the influence of high rotational speed on the axial measurement of static pressure gas can not be ignored.At the same time,the dynamic stiffness and dynamic damping of the bearing are obtained by the analysis of the dynamic characteristics of the static pressure gas bearing in the calculation of the disturbance.The increase of the eccentricity can effectively improve the damping of the bearing and the thickness of the gas film.The effect of stiffness and damping is gradually reduced,and at the same time the rotation speed can increase the effect of the main stiffness,and the increase of gas supply pressure can effectively improve the effect of stiffness.The influence of ripple error on static and dynamic characteristics of static pressure gas bearing is analyzed by the calculation model of ripple error.It is concluded that the influence of wavelength to the rigidity of vertical direction is larger,and the influence on damping is mainly in the horizontal direction;the amplitude of the circumferential wave stripe increases,the main stiffness varies greatly,and the amplitude of the axial ripple increases,the main stiffness is the main stiffness.The change of degree is mainly in the vertical direction;the effect of amplitude on damping is mainly concentrated in the horizontal direction,and the effect of circumferential ripple on static characteristics of static pressure gas bearing is greater than that of axial action.In view of the complicated changes in the flow field inside the throttle hole near the gas hydrostatic bearing,the flow field changes near the throttle hole are analyzed by the static model and the large eddy model.The turbulence effect is found near the throttle hole of the static pressure gas bearing,and the pressure is unstable and the shock wave(Ji Bo)is produced.The gas film region is gradually transformed from turbulence to laminar flow.Through the finite element analysis of theoretical calculation model and theory,the static and dynamic characteristics of static pressure gas bearing in different working conditions are obtained.It provides a certain theoretical basis for continuing to understand the static pressure gas bearing,and provides a reference basis for the design and manufacture of gas static pressure gas bearings.