Structural Characterization of a Novel Gas Foil Bearing With Nested Compression Springs: Analytical Modeling and Experimental Measurement

Abstract

A novel nested compression spring gas foil bearing (NSFB), which used a series of nested compression springs as compliant supporting structure, was proposed and designed. NSFBs can be easily manufactured and are able to provide a support with high stiffness, high damping, and tunable structural characterization in turbomachinery. An analytical model, which considered the effects of interaction and friction between adjacent springs, was established to predict the structural characterization of the compliant structure. Static and dynamic tests were conducted to analyze the structural performance of NSFBs. The predicted hysteresis loop of the compliant structure corresponded well with the measured results from the pull–push tests. A static test result comparison between an NSFB and a bump-type gas foil bearing (BFB) showed that the NSFB had a larger loss factor, which implied its superior damping performance. The effects of spring number and axial preload between adjacent springs on bearing performance were investigated. The static and dynamic loss factors of bearings with nested structures (47 and 39 springs) were similar to each other, but greater than the loss factor of bearings without nested structures (31 springs). The estimated static and dynamic loss factors of bearings with axial preload were significantly improved compared with bearings without axial preload.