Experimental And Analytical Investigation Of A Dynamic Gas Squeeze Film Bearing Including Asperity Contact Effects

Abstract

This thesis presents a theoretical and an experimental investigation of planar gas squeeze film bearings. The thickness and pressure profile of the gas squeeze film are obtained by simultaneously solving the Reynolds equation and the equation of motion for the squeeze film bearing. This work also accounts for the force due to surface asperity contact in the equation of motion. When the surfaces are in contact, the model predicts the contact force as a function of film thickness. Computational simulations are performed to study the development of the squeeze film from its initial state to a pseudo-steady state condition and to evaluate its load carrying capacity. For certain cases, the simulation results correlate well with the pre-established analytical results. However, corrections must be made to the analytical equations when they are used out of their effective range. In the experimental study, a squeeze film is developed due to an applied relative normal motion between two parallel circular plates of which one circular plate is effectively levitated. Theoretical results for the squeeze film thickness match qualitatively with its experimental counterpart. On successful testing of macro-scale gas squeeze film bearings, micro-scale bearing surfaces are fabricated. Experimental investigation of micro-scale bearings suggests that these bearings have significant potential for a wide range of applications in Micro-Electro-Mechanical Systems (MEMS).