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

In this paper, a novel numerical method was presented for THD analysis of the dynamic characteristics of the third-generation S-CO2 bump-type GFBs, considering thermal and centrifugal deformations. The proposed numerical method was validated by the experimental data of the eight dynamic characteristic coefficients of air-lubricated bump-type GFBs under different rotating speeds (21600rpm and 27600rpm) and static loads (20N-40N). The dynamic 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 (0.3-0.9). Calculations were performed for a wide range of perturbation frequencies (dimensionless perturbation frequencies 0.1-4.0) to encompass all possible excitation frequencies encountered in the bearing. The influences of operating parameters (high pressure and high temperature) and static loads on the dynamic characteristics of the third-generation S-CO2 bump-type GFBs were presented and discussed.