Effect of recess geometry on shock wave formation in circular gas bearings

An analytical method, based on the concept of shock wave formation in the bearing clearance, is used to develop a mathematical model by which the pressure distribution along the fluid film can be predicted. Based on this model, the limiting conditions for shock free operation are determined. The effects of recess geometry and inlet gas conditions are analysed. Experimental pressure distributions along the fluid film at different values of film thickness, supply pressure and rotating speed compare well with the theory. The analysis reveals that a bearing with a tapered recess has a higher resistance to shock wave formation than a conventional bearing having the same recess volume. Moreover, the tapered recess bearing has superior stability to the conventional bearing for the same recess depth.