Gas Foil Bearings for Oil-Free Rotating Machinery - Analysis Anchored to Experiments

Texas A&M Engineering Experiment Station, College Station TX

Investigators

Abstract

NSF PROPOSAL # 0322925 GAS FOIL BEARINGS FOR OIL-FREE ROTATING MACHINERY - ANALYSIS ANCHORED TO EXPERIMENTS LUIS SAN ANDRES TURBOMACHINERY LABORATORY MECHANICAL ENGINEERING DEPARTMENT TEXAS A&M UNIVERSITY MAY 16, 2003 ABSTRACT Further advancements in high performance turbomachinery operating at extreme temperatures mandate the development of gas film bearings/seals with coatings (solid lubricants) to procure compact units with improved efficiency in an oil-free environment. Gas foil bearings (GFBs) operate best at high speeds and temperatures, yet are limited in load capacity and prone to show rotordynamic instabilities. Current analyses cannot estimate accurately rotor-GFBs dynamic forced performance, thus resulting in extensive empirical developments. The absence of physical modeling on the material coatings exacerbates this deficiency. Thus, each GFB is essentially a custom piece of hardware, with resulting variability even in identical units, and limited scalability. The three-year research program will advance the technology by developing a comprehensive computational model predicting the static and dynamic forced performance of GFBs. The model will include thermo-elastic deformations of the foil and elastic members (bump strips), including hysteresis-dry friction from coatings and local contact zones. Exhaustive rotordynamic and materials tests with commercial GFBs will validate the model, including the identification of rotordynamic force coefficients and evaluation of coating endurance and wear. The research addresses to the needs of 22 U.S. turbomachinery manufacturers and users aiming to maintain their technological advantage. The proposed work is a signature program of the Mechanical Engineering department at Texas A&M University and an integral part of the recently established Mexican-American U.S. Latino Research Center (MALRC). The interdisciplinary MALRC addresses to Hispanic issues in Texas, and through the Turbomachinery Laboratory performs activities towards the recruitment and retention of Hispanic students in engineering and training the future faculty serving in Texas higher education institutions. Visit the following sites at Texas A&M University for further information: Rotordynamics Laboratory/Turbomachinery Laboratory Mexican-American Latino Faculty Association