Thermohydrodynamic Analysis of Static Characteristics for the Third-generation Supercritical Carbon Dioxide (S-CO2) Gas Foil Journal Bearings under High Pressure and Temperature

In this paper, a novel numerical method was presented for THD analysis of the static characteristics of the third-generation S-CO2 bump-type GFBs, considering thermal and centrifugal deformations. A full three-dimensional (3D) transient conjugate heat transfer numerical method was also developed to calculate convective heat transfer coefficients between the gas film and top foil and shaft. The present numerical method was validated by the experimental data of the static load, minimum film thickness and temperature for air-lubricated GFBs under different rotating speeds. Validations were also conducted based on the experimental data of load-carrying capacity (LCC) of air-lubricated GFBs at two ambient temperatures and varying ambient pressures (0.1-2.5atm). Furthermore, measured power loss of S-CO2 and N2 bump-type GFBs for different rotating speeds was also utilized to verify the accuracy of the present method for calculating the static characteristics of bearings lubricated by special mediums. The static characteristics were calculated and analyzed for the third-generation S-CO2 bump-type GFBs at different operating conditions, including ambient pressures (1.0-3.0MPa), ambient temperatures (300-600°C), and eccentricity ratios (0.1-1.0). The influences of operating parameters (high pressure and high temperature) on the static characteristics of the third-generation S-CO2 bump-type GFBs were presented and discussed.