Research On Optimization Design Of Multi-Wing Reconnection Electromagnetic Launch System

Electromagnetic launcher is an ejection device that accelerates a projectile to a certain speed by using electromagnetic thrust,which overcomes the inherent defect of the traditional chemical propellant whose initial velocity of the projectile is limited.And its emission efficiency is high,simultaneously,the energy cost is low and pollution-free,so it is considered to be an important milestone in the history of launch technology.Electromagnetic emission are mainly divided into rail,coil,reconnection three type,according to different structures.Among them,the reconnection type electromagnetic transmitter has the latest development,but it not only overcomes the serious electrical contact ablation of the first two types of emitters,but the radial contraction force is small,exit speed and the emission efficiency are greatly improved.Conventional reconnection electromagnetic launcher is limited to plate-like projectiles,greatly limiting the shape and size of the projectile.In response to this shortcoming,the research team adopted a tail-type reconnection electromagnetic propulsion method,which is a variant and evolution of the plated reconnection gun.The flank of projectile is accelerated and the intermediate entity is the payload.In order to obtain higher emission performance,it is necessary to simulate and analyze many factors affecting the launch performance of the transmitter.For this purpose,the following inquiry work was carried out:First of all,by the mathematical equations and motion equations of the reconnection electromagnetic transmitter,the force of the projectile in the driving coils is analyzed.Secondly,in order to establish a suitable launch mode physical model,comparing the emission efficiencies of different flank number transmitters,the overall performance of the four-wing reconnect type transmitter is found to be the best.Then the driving coil logarithm and the number of the projectile layer are optimized respectively,which determined four-wing,single-layer,eight-coil reconnection electromagnetic emission simulation model.Then,in the single-stage transmitter,by optimizing the four connection modes of the driving coil,there is an optimal connection method to make the system highest transmission efficiency.Based on the above,the effects of coil parameters,capacitor parameters and projectile parameters on the efficiency of the launch system are analyzed.The simulation results show that the optimal matching of each influence parameter can make the best emission performance.After optimization,the final exit velocity can reach 450.35m/s and the energy conversion efficiency can reach 35.44%.At last,multi-stage transmitter is analyzed,the coupling effect between the driving coils will not only affect the discharge current in the driving coil of the rear stage but also the eddy current of the projectile.Simulation results shows,when the level spacing remains small distance,the adjacent two coils pass opposite currents,and the rear-stage driving coils will generate superimposed induced electromotive force to enhance the eddy current induced by the projection surface,the connection mode of different driving coils in each stage changes the waveform of the discharge current,so the selection of the driving coil connection for each stage is particularly important.Then,the trigger position of each stage of the driving coil is optimized under the same capacitor parameters to ensure that the discharge time of the driving coil is synchronized with the position of the inductive coupling in the projectile and the coil.