A Thermohydrodynamic Model and Analysis for a Thrust Hybrid Gas Bearing System and Its Validation With Test Data

Abstract Air-lubricated gas bearings are highly advantageous for oil-free rotating machinery due to their cost-effectiveness, ease of assembly, and minimal drag friction, enabling high rotor speeds and long operational lifespans. Despite these benefits, existing computational models for gas bearings often lack accessibility for manufacturers or end-users and are limited by their applicability to specific geometries and conditions. This study introduces a comprehensive thermohydrodynamic model for a thrust hybrid gas bearing used in oil-free turbocharger applications, integrating heat and fluid flow models to develop a predictive tool for design and analysis. The model employs an efficient algorithm that iteratively couples the Reynolds equations with thermal energy transport equations, continuously updating temperature-dependent viscosity and film thickness. The energy balance reveals that the sum of drag power losses and heat convection into the film equals the thermal energy advected by the film. Thermocouples installed radially at the inner and outer diameters of each pad measure the temperature of the film to validate the thermal model. The test repeats and averages at various rotor speeds (2–22 krpm) and supply pressures (25–100 psi), demonstrating strong correlation between measured and predicted film temperatures. The thrust bearing film temperature shows an increase with rotor speed, showing a dominant hydrodynamic effect, likely due to the relatively small nominal clearance. The parametric analysis identifies supply pressure, gas density, and kinematic viscosity as the dominant factors influencing film temperature, highlighting their critical role in the performance of air-lubricated gas bearings. These findings provide valuable insights for the design and optimization of advanced bearing systems in high-speed, oil-free turbomachinery.