A Novel Thermal Management Approach for Radial Foil Air Bearings

Report No. ARL-MR-0749
Authors: Kevin Radil and CDT Zach Batcho
Date/Pages: July 2010; 22 pages
Abstract: We experimentally evaluated a novel thermal management technique for radial foil air bearings. The technique is based on injecting air directly into the internal circulating fluid-film to reduce bulk temperatures and axial thermal gradients. The tests were performed on a single top foil, Generation III, radial foil bearing instrumented with three thermocouples to monitor internal temperatures. A thru hole in the bearing shell coincident with the gap between the top foil's fixed and free ends provided entry for the injection air. The tests were conducted at room temperature with the bearing operating at speeds from 20 to 50 krpm while supporting 222N. Two different mass flow rates of injection air were evaluated for this method, 0.017 and 0.051 kg/min. Test results suggest that the air injection approach is a viable thermal management technique capable of controlling bulk temperatures and axial thermal gradients in radial foil air bearings.
Distribution: Approved for public release
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Last Update / Reviewed: July 1, 2010