| Electromagnetic coil emission technology is a modern emission technology that converts electrical energy into electromagnetic energy and uses electromagnetic force to accelerate the object to a predetermined speed.The electromagnetic coil can generate a pulsed strong magnetic field,which can be used in electromagnetic emission,electromagnetic molding,wave modulation inductors in pulse power supplies and other fields.However,electromagnetic coil usually work in the extreme physical environment of high current,high temperature rise,and strong stress.Under continuous discharge conditions,coil heat will continue to accumulate,resulting in excessive temperature,which will cause insulation aging and cause damage to the coil structure.Therefore,it is of great significance to reveal the temperature distribution law of the electromagnetic coil under continuous discharge conditions and control the temperature rise of the coil.Aiming at the problem that the temperature rise of the electromagnetic coil is too high during continuous discharge,this paper analyzes the temperature distribution law of the coil by using the multiphysics coupling calculation method to take the single-stage coil as the research object.Then,two water-cooled structures,the lead head and the side flange,were designed,and the influence of the water-cooled structural parameters on the heat dissipation effect of the coil was analyzed.Finally,a coil cooling scheme of phase change material is proposed,and the influence of phase change material parameters on the heat dissipation effect of the coil is analyzed.The main research contents are as follows:(1)The basic principles of electromagnetic induction coil emitters are introduced,the electromagnetic field control equation,temperature field control equation,fluid field control equation,boundary conditions and initial conditions in the multiphysics coupling calculation model are analyzed,and a coupling analysis method using finite element software is proposed.(2)2D and 3D electromagnetic coil models were established.The temperature rise difference of the two models after continuous discharge under natural heat dissipation conditions was analyzed.The effects of discharge interval and eddy current effect on the temperature rise of electromagnetic coil were studied.The results show that after continuous transmission,the maximum temperature difference between the two-dimensional and threedimensional coils is 4.5°C,and the error is 3.83%.When the discharge interval is 5s and 10 s,the coil can perform 5 consecutive transmissions,When the time interval is 50 s and 100 s,the coil can carry out 6 and 7 consecutive transmissions respectively.The eddy current effect has little effect on the temperature rise of the coil during continuous transmission.(3)Aiming at the problem of excessive temperature rise of continuous discharge coil,two water-cooled coil models of lead head and side flange are designed,and the influence of water flow rate,inlet water temperature and discharge time interval on the heat dissipation effect of the coil is analyzed.The results show that the time interval has the greatest influence on the heat dissipation results,followed by the inlet water temperature,and the flow rate of the water has the least effect.The water-cooled structure of the lead head increases the coil continuous discharge capacity from 7 to 9 rounds.The side flange water-cooled structure can make the coil heat generation and heat dissipation reach a balance when the discharge interval is 300 s,and the temperature is not rising,which can realize the continuous discharge of the coil.(4)A phase change material(PCM)electromagnetic coil cooling scheme is proposed.The effects of latent heat,thermal conductivity and melting temperature of phase change materials on the temperature rise of coil continuous discharge were analyzed.The results show that increasing the latent heat of the PCM during continuous discharge can effectively reduce the temperature of the coil.Increasing the thermal conductivity allows the PCM to dissipate heat from the coil more quickly,but the marginal benefit of increasing the thermal conductivity gradually decreases.Increasing the phase change temperature makes the melting time of PCM longer,but has little effect on the heat dissipation efficiency of the coil during continuous transmission. |
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