Static Characteristic Analysis of Aerostatic Porous Bearing with a Restricted Layer

Abstract

To enhance the gas-damping effect and improve the bearing performance, a restricted layer is applied on the surface of aerostatic porous bearings. Based on the gas lubrication theory, a mathematical model of an aerostatic porous bearing with a restricted layer is established, and two proportional coefficients, a permeability ratio δ and a thickness ratio γ, are proposed. Critical values of δ and γ are determined through sensitivity analyses of complex restriction-layer parameters. The static characteristics of aerostatic porous bearings with a restricted layer or an unrestricted layer are comparatively analyzed by using Fluent simulation. The results show that when δ ≈ 0.005 and γ ≈ 0.010, the load capacity and static stiffness of the restricted-layer aerostatic porous bearing are high; compared with the unrestricted-layer aerostatic porous bearing, the restricted-layer aerostatic porous bearing has a lower sensitivity to changes in the air supply area. The existence of the restricted layer not only enhances the throttling effect and reduces the mass flow rate, but also effectively improves the static stiffness of the bearing.

Keywords

aerostatic porous bearing / restricted layer / static characteristic / critical coefficient

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