Research On Steady State Temperature Field Characteristics Of Air-gap Non-immersed Hydraulic Motor Pump

The hydraulic motor pump is an innovative result of the development of hydraulic power unit towards quietness,high power density and green development.It replaces traditional fan cooling with liquid flow heat dissipation technology and combines integrated integration technology to give it advantages in noise and power density on the one hand.This is particularly prominent.On the other hand,the highly integrated structure also concentrates the various heat sources,which brings challenges to the heat dissipation of the motor pump and the temperature detection of the internal heat source.Therefore,a detailed analysis of the main heat sources of the hydraulic motor pump and clarification of its temperature field characteristics are important prerequisites for the optimal design of the heat dissipation structure of the hydraulic motor pump.In this paper,the air gap non-immersed hydraulic motor pump is used as the carrier,through simulation and experimental technology,combined with the basic theory of heat transfer,the main heat source—the temperature field characteristics of the three-phase asynchronous motor stator is studied.The temperature field distributions of the motor pump outer casing,inner casing,fluid and motor stator under different working conditions are obtained,and finally compared with the experimental measurement results.The details are as follows:First,establish a three-phase asynchronous motor model in the Maxwell software and perform numerical calculations to obtain the magnetic field lines and magnetic density distributions under no-load and full-load conditions.It is found that the motor has an enhancement effect on the magnetic field when there is a load.In turn,more losses are generated and finally converted into heat to be transferred to the components of the motor pump;furthermore,the corresponding motor core loss and winding loss under the load pressure of 0 MPa,6 MPa,12 MPa,and 18 MPa are calculated.By calculation,it is found that the core loss is smaller than the change of the winding loss with the load increase.The corresponding core loss values are 128.28 W,128.30 W,128.55 W,and 129.94 W,and the winding loss values are 579.91 W,631.48 W,712.45 W,1073.97 W.Secondly,in the STAR-CCM+ software,establish a thermo-fluid-solid coupling model of the motor stator,inner and outer casing and oil,and load the above loss values??into the stator core and windings respectively.The calculation results show that the temperature of the motor pump increases with the increase of load pressure.The highest temperature is located in the center of the motor stator winding.When the load pressure is 18 MPa,the highest temperature reaches 60.16 ℃,and the lowest temperature is at the end cover of the oil inlet;the heat transferred from the iron core to the inner shell is 11.1% higher than the heat transferred from the winding to the iron core,and 30.1% higher than the heat transferred from the inner shell to the fluid.Finally,15 thermocouples are arranged axially and spirally on the surface of the motor pump casing to obtain the temperature distribution law of the casing surface when the load pressure is from 0 to 18 MPa.The results show that the temperature of the case shows a rising trend with the increase of the load pressure,and the amplitude of the increase also increases;the case temperature near the stator is higher,and the temperature near the end cover of the oil inlet and outlet is lower.The shell temperature is the highest at the position where the stator is in direct contact,and its value can reach 44.7 ℃ when the load pressure is 18 MPa;comparing and analyzing the simulation calculation and experimental measurement results when the load pressure is 6 MPa and 18 MPa,it is found that the temperature change trends of 15 temperature measurement points are basically the same,which further confirms the validity of the steady-state temperature field simulation results.