Research on load characteristics of aerostatic journal bearing with pocketed orifice-type restrictor

This paper presents a simulation study of load characteristics of aerostatic journal bearing with pocketed orifice-type restrictor. In order to analyze the influence of characteristic parameters of aerostatic journal bearing and lubricating gas, the computational fluid dynamics (CFD) software, FLUENT, is adopted and the whole three-dimensional models are built which contain the orifices and air chambers. The simulation results show that the velocity vectors of lubricating gas undergoes a significant change when the gas flows through the orifice and air chamber, and gas flow field in orifice-type restrictor should be taken into account when estimating aerostatic journal bearing performance. Furthermore, the paper has discussed the effect of axial location of orifices, supply gas pressure, rotating speed and eccentricity ratio on carrying capacity, stiffness and mass flow rate. When the aerostatic journal bearing works at a low rotating speed, static performance will provide the dominating load capacity, while when rotating speed ω is more than 5×10⁴rpm under high eccentricity ratio, the dynamic performance is the main source of load capacity.