| Electromagnetic launch technology is a kind of launch technology which can exert electromagnetic force on the launcher through the interaction of current and magnetic field,so that it can achieve the desired flight speed in a very short time.It has the advantages of low cost,green energy saving,large acceleration and high launching efficiency.Electromagnetic launcher is mainly divided into rail type electromagnetic launcher and coil type electromagnetic launcher.At present,the existence of electrical contact,high current and friction will cause the ablation of the track,so the service life of the track is relatively low.while the coil structure has large radial force,and the higher the exit speed is,the higher the requirements for the synchronous measurement and control system are,so it is difficult to achieve ultra-high speed launch.In general,these two launchers can accelerate the projectile to the specified speed in a shorter time than Lim(Linear induction motor),but their energy conversion efficiency is lower than Lim.Therefore,in order to improve the launching efficiency,this paper proposes two special structures of coil electromagnetic launcher,and makes theoretical analysis,simulation and experimental research.In order to solve the problem of low energy conversion efficiency of coil-type electromagnetic launcher,this paper proposes a new type of single-stage TL-type electromagnetic launcher(SS-TL-EL).Firstly,the electromagnetic characteristics of SS-TLEL are analyzed in principle.Then,a simulation model is established to analyze the effects of the changes of energy storage capacitor voltage,capacitor value,initial trigger position and other parameters on the efficiency of the launch system.The launching effects of SS-TL-EL and traditional single-stage synchronous electromagnetic launcher(TSSSEL)are compared under the same conditions,and the launching efficiencies are 17.9% and 10.7% respectively.The simulation results are analyzed,and the comparison experiments are carried out under low voltage.The experiments show that SS-TL-EL has higher launching efficiency than TSSSEL.Then,aiming at the problem of low launching efficiency of multipole moment electromagnetic launching technology,this paper proposes a tortuous synchronous induction coilgun(TSIC)based on the existing synchronous induction coilgun configuration,which can realize both linear acceleration and spin acceleration of the armature.Spin of projectile armature is helpful to solve the problem of dynamic stability of projectile at high speed exit.Firstly,the force of TSIC is analyzed in principle.Then a simulation model is established to simulate and analyze the influence of different initial torsion angles on TSIC launch performance.Although the simulation results show that TSIC improves the launch efficiency from 0.183% to 0.866% compared with the traditional multipole moment rotation acceleration model,there is still a gap in the launch efficiency compared with the traditional synchronous coilgun.Then,the discharge circuit is improved to enable the armature to accelerate twice in the launching process,increasing the launching efficiency to 2.04%,and comparative experiments are carried out under low voltage.The experiments show that the TSIC experimental data are close to the simulation data,and the TSIC after the improvement of the external circuit has higher launching efficiency under the same capacitance voltage.Lastly,the coupling effect between two stages of electromagnetic launcher is theoretically analyzed.SS-TL-EL and TSSSEL are assembled to form a two-stage electromagnetic launcher,and its simulation verifies the correctness of the theoretical analysis.The influence of current direction of two-stage coil,discharge interval and two-stage interval on launching effect is analyzed through simulation calculation.On this basis,the launching performance of the two-stage coil electromagnetic launcher composed of SS-TL-EL and TSIC is discussed and analyzed. |
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