Extended 3-D Thermo-Hydrodynamic Model of Radial Foil Bearing

A turbine simulator with foil bearing supports mimicking 50kW power generation gas turbine was designed. In this paper, the 3-D thermo-hydrodynamic (THD) model developed for single radial FB was further extended to the turbine simulator configuration by extending the solution domains to surrounding structures. In addition, a computational fluid dynamic (CFD) model on the leading edge groove on the foil bearing was developed for better prediction of inlet thermal boundary conditions for the bearing. Several case studies are presented for hydrodynamically preloaded three-pad radial FB in the hot section. It is found that both bearing and rotor should be provided with cooling air to maintain both the rotor and top foil below 300°C. It is also found that the higher thermal contact resistance between the rotor and hot impellers reduces the axial temperature gradient of the rotor.