In this paper, a thermo-hydrodynamic model of the bump foil thrust gas bearing is developed, which solves the coupled gas film three-dimensional energy equation, non-isothermal Reynolds equation, and the foil deformation equation. The effects of bearing speed, thrust load, and external cooling gas on the bearing temperature field are calculated and analyzed. The test rig of foil thrust gas bearing was built to measure the bearing temperature under different working conditions. Both simulation and experiment results show that there exist temperature gradients on the top foil both in the circumferential and radial directions. The simulation results also shows that the top foil side of the gas film has the highest temperature value in the entire lubrication field, and the position of highest temperature moves radially inward on the thrust plate side as the rotor speed increases. The gas film temperature increases with the increasing rotor speed and bearing static load, and rotor speed has greater effects on the temperature variation. Cooling air flow passing through the bump foil is also considered in the simulations, and the cooling efficiency decreases as the mass of gas flow increases.

Traditional bump foil bearing, though widely used, is considered to have the problem of inadequate load capacity due to the effect of foil sag between adjacent bumps. In this paper, the thick top foil is applied to cope with the heavy load conditions, which has one order of magnitude larger top foil thickness than traditional top foil. Thick plate and curve shell models are developed to calculate the load-carrying performance of thick top foil bearing based on contact mechanics, and the sag ratio is introduced to describe the degree of foil sag and estimate the bearing load capacity. The impacts of top foil thickness on the stiffness of bearings in different sizes as well as on the adaptability to rotor tilt are discussed. The results indicate that the thick top foil (tt = 2 mm) bearing performs a nearly 100% enhanced load capacity at small gas film thickness whether rotor tilts or not. Thick top foil will increase the bearing stiffness of small size (d = 35 mm) and tends to have little influence on large-size bearing stiffness (d = 70 mm).

Gas foil bearings have important and wide applications in high-speed turbomachinery, generating low frictional lubricating gas film in series with underlying elastic foil structures to support the rotor system. Their dynamic performance is of vital significance in maintaining the rotor stability as well as in depressing rotor vibrations. This paper conducts a comprehensive review on dynamic performance studies conducted on gas foil bearings, including research on the dynamic stiffness and damping coefficients, bearing stability, nonlinear vibrations of the rotor–bearing system, and active methods for controlling rotor dynamic motions. This review provides clear observations towards the developments and iterations of the models, methods, and experiments of these studies.