Review of Technologies Used in Gas Journal Bearing Test Rigs

Abstract

Abstract Foil bearings are the most prevalent gas bearing technology in use today. Foil gas bearing technology development requires a two-fold approach of analytical and experimental research. Analytical simulation can be used to better understand the underlying physical principles in detail, though this is not trivial due to complex interactions of structural, thermal, and fluid dynamics effects. Targeted experimental testing may then be used to validate the models. However, in practice, foil gas bearings have relied on simplified analytical tools, experience, and empirical approaches to validate and heuristically tune new bearing designs. Static load test rigs have been used to quantify steady-state performance like drag torque and load capacity as well as transient performance like lift-off speed and start/stop wear. Dynamic load test rigs have primarily been used to characterize the stiffness and damping coefficients of the bearings. This paper reviews test rigs employed over the last several decades, focusing on static and dynamic rigs for foil gas journal bearings. Technologies and considerations for the necessary test rig functions are covered: drive system, rig topology, static load mechanism, torque measurement, dynamic excitation and response measurement, and means to test in various gas conditions. A primary goal of this paper is to serve as a reference to future researchers embarking on a new gas journal bearing test rig design who wish to understand the state-of-the-art in this area.