Recent breakthrough improvements in

Recent breakthrough improvements in foil gas bearing load capacity, high temperature tribologicalcoatings and computer based modeling have enabled the development of increasingly larger and moreadvanced Oil-Free Turbomachinery systems. Successful integration of foil gas bearings intoturbomachinery requires a step wise approach that includes conceptual design and feasibility studies,bearing testing, and rotor testing prior to full scale system level demonstrations. Unfortunately, thecurrent level of understanding of foil gas bearings and especially their tribological behavior is ofteninsufficient to avoid developmental problems thereby hampering commercialization of new applications.In this paper, a new approach loosely based upon accepted hydrodynamic theory, is developed whichresults in a “Foil Gas Bearing Performance Map” to guide the integration process. This performance map,which resembles a Stribeck curve for bearing friction, is useful in describing bearing operating regimes,performance safety margins, the effects of load on performance and limiting factors for foil gas bearings.