System Optimization And Experiment Investigation Of Induction Type Electromagnetic Launcher

The electromagnetic launch is that when the electromagnetic force works,the electromagnetic energy is transformed into kinetic energy which is used to launch projectile (armature).The technology of electromagnetic launch has been a leap in the fields of propulsion technology in recent years.It has opened up a new avenue to meet the special requirements of propulsion with ultra high speed and big mass.Its merit of low propulsion cost has especially attracted the attention of all countries.The technology of electromagnetic launch is applied in the field of the national defense and civilian industries , such as aircraft launch system ,electromagnetic gun,linear electromagnetic induction pumping units,ramming machine and so on.In the course of the electromagnetic launch development,there are three basic types of the electromagnetic launcher: the track gun, the coil gun and the reconnection gun. The coil gun, which is also named as induction type electromagnetic launcher,can be interpreted as a cylindrical linear motor.Its characters are as follows:Because of the magnetic suspension effect,there is no fiction between tube and projectile in acceleration process;simple structure; wide range of launch quality;different shapes of the projectile;simple energy source ; high initial velocity ; good controllability and excellent performance.Therefore,only the coil electromagnetic launcher is researched in this paper.The process of the electromagnetic launch is a transient process,so the interaction between the stator windings and projectile varies with the change of time.Consequently,in order to design an electromagnetic launch system which has good working conditions,it is rather necessary to build a numerical simulation model.After analyzing the characteristic of driving coil circuit and kinematics,the system equation of the three stages electromagnetic launcher is built.The system equation is nonlinear constant differential equation.The projectile is equivalent to some slices,which makes the self-inductances,mutual inductances and mutual inductance gradient are closer to the actual situation. According to the symmetry of the parameters,the assignment table is used to decrease the calculation time.The Treanor algorithm,which has better stability,is used to solve the nonlinear constant differential equations,and the stable solution is obtained.A computer simulation program which is especially appropriate to the single stage coil gun is designed,and the simulation results satisfactorily agree with the experimental data.To enhance the projectile efficiency of the system,the discharge loop is improved.Experiment results indicate the projectile efficiency of the improved system increases when the energy equalizes.