Numerical investigation of pressure-equalizing groove configuration effects on gas bearing performance

High-speed rotating machinery has extremely high requirements for the performance and reliability of aerostatic bearings, and the design of pressure-equalizing groove structure is a key factor determining the performance of aerostatic bearings under high-speed conditions. At present, research on the influence of pressure-equalizing groove structure on the performance of high-speed aerostatic bearings is still relatively limited. In this study, aerostatic thrust gas bearings with three pressure-equalizing groove structures (rectangular, fan-shaped and drop-shaped) were designed, and their performance characteristics were comprehensively analyzed by numerical simulation method. A CFD model of the bearing was established based on the Navier-Stokes equations and the model accuracy was verified. The performance of bearings with each structure under different working conditions of air film thickness, supply pressure and rotational speed was explored. The study found that the shape of pressure-equalizing groove has a significant impact on the load-carrying capacity, pressure distribution, stiffness and stability of the bearing. Under high-speed conditions, vortices in the groove critically affect the pressure distribution in the high-pressure zone of the bearing, which in turn determines the load-carrying capacity. Fan-shaped and drop-shaped grooves can effectively suppress vortices due to their divergent structures, and their load-carrying capacity and stiffness during high-speed operation are superior to those of rectangular grooves, while rectangular and fan-shaped grooves have smaller pressure fluctuations and exhibit better stability. There is a clear correlation mechanism between the divergent characteristics of different pressure-equalizing grooves and vortex suppression. Fan-shaped and drop-shaped grooves can promote the expansion of the high-pressure area of the air film and enhance the hydrodynamic effect, while the complete vortex in the rectangular groove limits the development of the high-pressure area. The research results provide theoretical support for the design and optimization of aerostatic bearings, and contribute to the research and development of high-performance bearings adapted to high-speed rotating machinery.