Research On Inductive Coil Launch System Based On Energy Conversion Rate

As the offensive and defensive balances continue to lean toward the offensive side,the battlefield survival environment of armor vehicles is getting worse.In the 21 st century,human urbanization will enter an unprecedented height,and military operations aimed at destroying enemy's vital forces,controlling strategic resources,and combating hostile regimes will be more around the city,and urban combat is inevitable.Under this circumstance,the active protection system should be vigorously developed to form a three-dimensional multi-level armor protection system to effectively face the multi-angle anti-tank weapon attack in the urban combat.Compared with the traditional active protection system,the active electromagnetic armor has the characteristics of faster response,safe energy storage and good installation adaptability.In the visible future,with the exhaustion of fossil energy,the human war will enter the power era,and the electromagnetic armor can be more compatible with all-electric tanks and makes it possible to intercept electromagnetic shell with much higher initial velocity.In order to provide some reference for the design and development of active electromagnetic armor,this paper takes planar coil electromagnetic launch as the research object,based on self-developed launcher.Combing the theory,experiment and numerical simulation,focusing on the energy conversion during the launch process,the main work is as follows:(1)According to the principle of the planar coil active electromagnetic armor launcher,the circuit equation and motion equation of the launching process are derived.The planar coil active electromagnetic armor launch test platform is built,which can achieve the maximum launching energy of 3kJ.And the flight process of the flying plate can be recorded in order to calculate the initial velocity of the flying plate,and analyze its launch efficiency.(2)The electromagnetic launch test under different energy storage is carried out,that is,under different storage capacitors and initial charging voltage,the current-time history curve is collected and the initial velocity of the flying plate is calculated to obtain the launch efficiency.The effects of silicon stack on the launch efficiency were studied.On the basis of this,the simulation research equivalent to the experimental loading conditions was carried out.The simulation and experimental data were compared,so the rationality and accuracy of the simulation were verified.The effects of silicon stack and different energy storage on the launch efficiency were studied,and the mechanism is analyzed.Finally,the conclusion is drawn that the efficiency increases with the increase of capacitance and initial charging voltage,but the rate of increase gradually decreases.Under the same energy storage,the silicon stack can greatly improve the launch efficiency.(3)Based on the manufacturing process of the coil,the decisive geometric parameters in the coil forming process are obtained,namely the length of the copper strip,the thickness of the copper strip,the height of the copper strip,the outer diameter of the core rod and the inner diameter of the launching base,etc.Using 3D modeling software,the model is established and imported into simulation,and the initial launch velocity and current in the coil are calculated.The influence of different parameters on the launch efficiency is studied,and the length of the copper strip is determined as the major factor.Base on the equation of motion,several important factors affecting the initial velocity of the flying plate are derived.According to the calculation principle of the coaxial ring mutual inductance,the mutual inductance between the flying plate and the coil is calculated.It is concluded that under the condition of certain energy storage conditions,the initial velocity of the flying plate is proportional to the length of the copper strip.(4)Finally,the effect of the package of the launcher on the launch efficiency and the coupling between the flying plate and the coil is studied by numerical simulation.The material and size of the package and the mounting position of the package relative to the coil are analyzed.The influence of mutual inductance between the flying plate and the coil,the eddy current loss distribution and the total eddy current loss in the package are calculated accordingly.And,the high magnetic permeability material can compress the main magnetic field in the launcher and strengthen the coupling.The low conductive material can reduce the induced eddy current and the eddy current loss.The eddy current loss at the bottom of the package is larger than that of the sidewall.The reduction of the overall size is beneficial to reduce the eddy current loss,but its effect is affected by the skin effect,and the coupling between the flying plate and the coil is weak.Increasing the mounting distance of the package to the coil can greatly reduce the internal induced eddy current,but weakens the coupling between the flying plate and the coil.