Bearing Capacity Based On CFD And Stability Analysis Of Radial Gas Dynamic Pressure Bearing

With the development of high and new technology,the rotating machinery used in engineering has put forward new requirements for its supporting bearings.The traditional sliding bearings and rolling bearings with lubricating oil as the medium can no longer meet them,so gas bearings have become the best choice.Gas bearings have a wide range of application prospects in engineering,but their low bearing capacity and easy instability in operation seriously affect the practical performance.At the same time,due to the high manufacturing precision requirements of gas bearings,it is difficult to design through experiments.and research.In this paper,the radial gas dynamic pressure bearing is taken as the research object,and the gas film pressure distribution and gas film bearing capacity of the gas dynamic pressure bearing are studied by computational fluid dynamics(CFD).The design and production give certain theoretical guidance.The main research contents and achievements include:The effects of rotational speed,eccentricity and aspect ratio on the gas film pressure distribution and the gas film bearing capacity were mainly studied for the smooth journal radial gas dynamic pressure bearing.The results show that:with the increase of rotational speed under the same eccentricity and aspect ratio,the variation trend of the maximum pressure of the air film and the bearing capacity of the air film increases nonlinearly;under the same rotational speed and aspect ratio,with the increase of the eccentricity,the air film increases.The changing trends of the maximum pressure and the air-film bearing capacity increased nonlinearly.(2)Herringbone groove radial gas dynamic pressure bearing mainly studies the operating parameters(speed,eccentricity and air film gap)and groove parameters(slot angle,groove width ratio and groove depth ratio)for its gas film pressure distribution and gas film load.influence of force.The results show that with the increase of rotational speed and eccentricity,the variation trends of the maximum pressure of the air film and the bearing capacity of the air film both increase nonlinearly,and with the increase of the air film gap of the bearing,the maximum pressure of the air film and the bearing capacity of the air film increase.The variation trend decreases nonlinearly;with the increase of the slot angle,the variation trend of the maximum pressure of the gas film and the bearing capacity of the gas film decreases nonlinearly.The bearing capacity of the gas film shows a trend of increasing first and then decreasing,and the trend is nonlinear.(3)The running stability of the smooth journal radial gas dynamic pressure bearing and the herringbone groove radial gas dynamic pressure bearing are analyzed from different angles.The results show that the main reason affecting the running stability of the smooth journal radial gas dynamic pressure bearing is the half-speed whirl phenomenon.With the increase of the rotational speed,the smooth journal gas dynamic pressure bearing will eventually become unstable and damaged;The main reasons for the stability of the radial gas dynamic pressure bearing are the rotational speed and the bearing air film gap.With the increase of the rotational speed,the critical mass of the herringbone groove radial gas dynamic pressure bearing decreases,which makes it prone to instability and damage.,With the increase of the bearing air film gap,the critical mass of the herringbone groove radial gas dynamic pressure bearing increases,making it less prone to instability and damage.The research results of this paper can provide some theoretical guidance for the design of radial gas dynamic pressure bearings,and also provide a theoretical basis for judging the running stability of radial gas dynamic pressure bearings.