Study on thermal deformation of high-pressure aerostatic thrust bearing in uneven temperature field

As for high-pressure aerostatic thrust bearing, the notable increase of air supply pressure makes gas film pressure and flow velocity increase rapidly. The two assumptions of fully developed laminar boundary layer and isothermal flow in parallel gas film are no longer valid, which are generally considered suitable for aerostatic thrust bearing with low air supply pressure. Based on the coupling analysis of the air flow field in the channel clearance of the bearing and the conjugate heat transfer of the bearing discs, the development process and flow regime of the velocity boundary layer and the temperature boundary layer in the parallel gas film are investigated. The results of conjugate heat transfer analysis for bearing discs made of various materials show that, isotropic thermal conductivity is the main factor affecting the heat flux, temperature distribution on the interface between solid wall and high-speed airflow in the channel clearance, and the temperature gradient inside the bearing discs. Further research on the relationship between the net thermal deformation, net elastic deformation caused by gas film pressure as well as total deformations of the bearing discs and the material properties shows that, the coefficient of thermal expansion is a crucial parameter affecting the net thermal deformation, but the total deformations of bearing discs also depend on the pressure load exerted by gas film. In the range of the working conditions specified in this study, structural steel is a more suitable choice than stainless steel or invar. Consequently, this research provides meaningful guidance for the designs of high-pressure aerostatic thrust bearings.