Performance calculation and experimental study on a hydrostatic journal bearing for turbopumps

An experimental hydrostatic journal bearing intended for the reusable liquid rocket engine turbopump was designed and investigated through numerical calculation and experiments. The Reynolds equation for incompressible laminar fluid was numerically solved based on its linear characteristic and the static performance (load capacity and mass flow rate) of the bearing lubricated with water and liquid nitrogen versus eccentricity ratio and supply pressure was calculated and analyzed. The flow characteristic of the bearing restrictor was studied through experiment and the bearing lubricated with water was also tested. The flow characteristic experiment of the restrictor shows that the flow coefficient of this non-typical restrictor is much larger than that of orifice restrictors. The numerical results show that the mass flow rates of the bearing lubricated with water and liquid nitrogen are very close to each other under the present research condition. The high-speed water lubrication experiment indicates that the equilibrium position of the shaft in the bearing is mainly determined by the supply pressure and the bearing shows no obvious hydrodynamic effect in the speed range of 0~30 000 r/min. Both numerical and experimental results show that the mass flow rate of the hydrostatic journal bearing is largely independent of the eccentricity ratio. The numerical results of the bearing lubricated with water and liquid nitrogen, together with the water lubrication experimental results provide a reference for further cryogenic lubrication experiments.