Study On Heat Transfer Characteristics Of Active Cooling In Electromagnetic Railgun

Electromagnetic launching technology is a new launching technology that uses electromagnetic force to promote the movement of the projectile.Since the 21 st century,electromagnetic launching technology has a series of advantages such as high controllability and strong adaptability,and has achieved considerable development.Electromagnetic railguns relying on electromagnetic launch technology have broad prospects of application in fields of military,aerospace,and civil fire protection.The electromagnetic railgun generates Considerable amounts of heat when it is launched.This heat mainly comes from the Joule heat generated by the resistance of the rail body and the contact resistance of the pivot rail and the sliding friction heat generated by the armature movement.They are deposited on the rail,causing the local temperature of the rail to rise sharply.They are deposited on the orbit,causing the local temperature of the orbit to rise sharply and damage the orbit,and thus affecting the launch performance.In order to solve the problem of heat accumulation encountered in engineering applications of electromagnetic railguns,it is necessary to cool the rails.This study focused on the experimental electromagnetic railgun.First,a threedimensional simulation model of the electromagnetic railgun launch process was established,and the finite element method was adopted to analyze the temperature of the orbit after the launch,and the temperature space-time distribution characteristics of the orbit were obtained;Then,an internal cooling experimental system based on the temperature distribution of the electromagnetic track was built,and the axial temperature variation of the track during the cooling process of the electromagnetic track was analyzed,and the influence of different flow rate on the cooling effect was experimentally studied.Finally,on the basis of the experiment,the internal cooling model of the electromagnetic railgun,the space-time distribution and evolution of the track temperature were deeply studied.The results of numerical calculation showed that the heat conduction in the orbit plays a leading role in a short time after launch.After that,the convective heat exchange of the cooling medium started to take effect,and the heat was taken away by the fluid flow.Increasing the flow rate of the cooling medium within a certain range can obtain a more uniform temperature distribution and a better cooling effect.In the mode of continuous firing,the heat deposited on the track varied in a sawtooth waveform with time,and gradually tended to heat balance.This study revealed the law of heat change on the track during the active cooling process inside the electromagnetic track,clarified the influence of different flow rates on the heat transfer effect,and provided a theoretical basis for the track heat management strategy.