Abstract:For the lubrication problem of centrifugal compressors,a dynamic pressure air bearing with R134a as the working medium was proposed.Based on the Reynolds equation of fluid lubrication,starting from the comparison of refrigerant and air flow,the gas bearing was modeled and analyzed through theoretical assumptions.Numerical analysis was used to calculate and analyze the threedimensional gas film flow field,and the gas film thickness distribution,gas film pressure distribution,bearing capacity and power loss of the dynamic pressure bearing were obtained.The results show that the bearing capacity of the gas bearing using R134a as the working medium is about 50% of that using air as the working medium under the same conditions,and the bearing capacity of both is increased with the increase of the fanshaped tile opening angle and rotation speed.The height and pitch ratio are increased first and then decreased,and decreased with the increase of the minimum initial air film thickness.Under the same conditions,the power loss of the system using R134a as the working medium is about 60% of that using air as the working medium.The power loss of the two systems is most affected by the minimum initial gas film thickness and speed.The higher the speed and the smaller the minimum initial gas film thickness,the greater the power loss of the two systems.