Gaseous cavitation characteristics of high-speed hydraulic electric motor-pump based on centrifugal pressurization: A numerical study

Hydraulic electric motor-pump is an integrated hydraulic power unit, raising rotational speed will further increase its power density. However, gaseous cavitation at high speed is the primary problem to be solved. In the present study, a new but simple centrifugal pressurization structure that integrated with the hollow shaft of hydraulic electric motor-pump was proposed to increase the inlet pressure of conjugated straight-line internal gear pump, and then to suppress gaseous cavitation at high speed. The numerical simulation is the main means of this work to investigate the gaseous cavitation characteristics of high-speed hydraulic electric motor-pump. In addition, a common conjugated straight-line internal gear pump model was developed as a reference to evaluate the pressurization effect of centrifugal tubes in terms of gas volume fraction. The simulation results present that compared with the significant increase of the suction chamber pressure of conjugated straight-line internal gear pump due to increasing the inclined angle of centrifugal tubes, the blocking effect of its inside wall to the fluid flow can be ignored. Under the same gas volume fraction in rotating volume, the rotational speed of hydraulic electric motor-pump is much higher than conjugated straight-line internal gear pump due to the pressurization effect of centrifugal tubes. On the premise of no obvious gaseous cavitation of centrifugal tubes, the recommended speed of hydraulic electric motor-pump is up to 13,000 r/min.