Abstract: Based on the principle of centrifugal pump and the idea of compact design, an electric-motor-pump is developed. It is integrated by an electric motor, a hydraulic vane pump and a port-plate centrifugal pump as a compact hydraulic power unit. The vane pump is as the main pump of the unit. The port-plate centrifugal pump is designed specially for the main pump to improve the suction performance of the electric-motor-pump. The integrated pump demonstrates some attractive advantages such as more compact structure, lower noise, higher efficiency and no external leakage. By computational fluid dynamics (CFD) method, the effects of the main structural parameters of the port-plate centrifugal pump on its outlet pressure and the efficiency are investigated. The design rules for the port-plate centrifugal pump are concluded. The simulation results show that the port-plate centrifugal pump can raise the inlet pressure of the main pump obviously. When the slope angle of the eccentric tube is 45° and the bias angle is between 45°~60°, the maximum power consumption is only about 0.41% of the electric-motor-pump, which also shows that the port-plate centrifugal pump almost do not influences the whole power characteristics of the electric-motor-pump. Its efficiency can be above 95 percent, and the whole efficiency of the centrifugal pump including the outlet channel is 22%. Power loss occurs due to eddy flow from the outlet of the centrifugal pump to the outlet channel to the main pump.

Key words: Electric motor pump, Flow analysis, Port-plate centrifugal pump, Structure optimization