Study on the load-carrying characteristics of flash hydrogen gas foil bearings-rotor system in a subcooled liquid hydrogen centrifugal pump

Flash hydrogen gas foil bearings-rotor system shows promise for supporting a subcooled liquid hydrogen centrifugal pump in refueling stations, offering self-lubrication, oil-free, and ultra-high-speed capability. However, its load-carrying characteristics have not yet been reported. Therefore, a thermo-elasto-hydrodynamic model is developed to investigate load-carrying performance under cryogenic conditions. Results indicate that increasing temperature increases load capacity, minimum film thickness, film pressure, power, and torque, while attitude angle decreases. Performance improves with flash-gas molecular mass in the order H 2 < He < CH 4 < N 2 < Ar. Eccentricity ratio and nominal clearance are the dominant factors, contributing 45.67% and 18.92% to load capacity, 52.34% and 15.67% to power consumption, respectively. Optimal combination is pressure 1.0 MPa, temperature 39 K, rotational speed 20000 r·min −1 , eccentricity ratio 0.7, nominal clearance 20 μm, and friction coefficient 0.07. Compared with average values, the optimal combination increases load capacity by 51.2% and reduces power by 81.7%.