| The design of internal flow passage holds a significant position in total design of non-oil-immersed air gap type hydraulic motor vane pump. The research on internal flow characteristics of electric motor-pump can provide technical supports for reasonable and accurate design of internal flow passage. Port-plate centrifugal pump component in electric motor-pump was used to increase the inlet pressure of main pump and palyed a role of achieving optimal flow distribution of main so that main pump could quiet work with high efficiency under high rotate speed. The cooling flow channel was designed to make sure the good heat dissipation of electric motor-pump which resulted in the realization and reliable operation of a high power-density electric motor-pump.The suction performance of hydraulic pump is an important factor that restricts its integration and high speed work. A port-plate centrifugal pump was designed to play a role of charging pump to boost the inlet pressure of main pump in electric motor-pump, which could guarantee the sufficient suction of main pump at high speed. The internal flow characteristics of port-plate centrifugal pump were researched based on MRF model of software Fluent to explore the influence rule of structure parameters to charging effect of port-plate centrifugal pump. The results of flow field calculation showed that charging effect of centrifugal pump was enhanced with the increase of centrifuge tube’s diameter,centrifuge tube’s number and slope angle of centrifuge tube. Besides within certain limits,the charging effect was weakened with the increase of bias angle of centrifuge tube and diameter of inlet channel and enhanced with the inlet distribution radius of centrifuge tubes.This research can serve as references of the design of port-plate centrifugal pump.To guarantee the sufficient suction of main pump working in high rotate speed in electric motor-pump, a structure of introducing balance slots and guide slots into flow distribution channel of main pump was proposed by researching its internal flow characteristic, which aimed at solving the problems that the delivery flow of port-plate centrifugal pump had high pressure difference between outside and inside of flow distribution channel of main pump and the flow resistance when rotary flow flows through suction flow channel of main pump was high.The results of flow field calculation showed that balance slot communicated the pressure between outside discharge channel and inside assistive channel and outlet pressure difference of them was approximately kept at a low constant value.The formation of vortex was avoided and the flow resistance was decreased when rotary flow flowed through discharge channel because of the direction function ofguide slot,which led to the obvious increase of inlet flow of discharge channel.The outlet static pressure of flow distribution channel increased with guide slot wrap angle,and when guide slot wrap angle was larger than 80 degree,outlet static pressure of discharge channel increased by 10% and that of assistive channel increased by 15.4%.This research can serve as the references of flow distribution design of main pump.The cooling performance of motor is one of important factors that guantee the safe,stable and highly efficient operation of electric motor-pump with high power density, so the cooling flow channel of electric motor-pump should be designed in a reasonable way to make motor has a good cooling effect and make itself has a lower pressure drop loss. Several kind of cooling flow channels were introduced and made a comparison analysis. The spiral deformation flow passages were finally introduced into the cooling flow channel because of its outstanding heat transfer enhancement performance and low pressure drop loss and its structure parameters were determined. At the same time, the inner flow field of electric motor-pump was simulated and the simulation results showed that longitudinal vortexes existed in the spiral deformation flow passages, which led to the radial miscibility of fluid enhancing the heat transfer effectiveness. The pressure drop loss from inlet of electric motor-pump to inlet of main shaft central hole was 2600.21 Pa which was smaller. This research can serve as references of the design of cooling flow channel.The internal flow of electric motor-pump have a close relationship with the changes of working condition of electric motor-pump. To guarantee that inlet pressure meet the requirements of electric motor-pump, the minimal pressure should be gained. By using software Fluent to simulate the inner flow field of electric motor-pump, some results has been revealed. Outlet pressure of discharge channel and assistive channel decreased linearly with the increase of oil viscosity and discharge flow and increased with the increase of rotate speed.The out pressure varied with angle of rotation in process of centrifugal pump working and they had minimum when the angle was 58°. The pressure drop loss in cooling flow channel increased with the increase of discharge flow and with the fall of working temperature. The minimum inlet pressure of electric motor-pump was-0.13 bar in the condition of extreme operation and the demand for minimum inlet pressure of electric motor-pump was lower compared with that of main pump. |
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