Study On Electromagnetic Temperature Field Of Electromagnetic Induction Coil Launcher

The electromagnetic coil emission technology uses the electric energy as the power energy source to generate the electromagnetic force to launch the object,which has obvious advantages compared with traditional artillery.However,the requirement of electromagnetic coil launchers for high-speed motion makes coils store more energy and consume more energy.Under the condition of continuous pulse discharge,the temperature will be over-accumulated,which will lead to coil insulation damage,armature melting and so on and eventually lead to launch failure.Therefore,it is of great significance to accurately calculate the distribution of the continuous pulse discharge temperature of the electromagnetic coil launcher and adopt the temperature control measures.Taking the single-stage induction coil transmitter as the main research object,the detailed model of the coil launcher is established,and the internal temperature distribution of the electromagnetic coil launcher is studied by using the multi-physical field coupling calculation method.The main contents are as follows:(1)The basic principle of electromagnetic induction coil launcher is briefly introduced,and the current wire method based on lumped parameters is proposed to calculate the electromagnetic-temperature field under the movement of electromagnetic induction coil launcher and discuss the influence of armature splitting and whether the temperature affects the thermal parameters.Study shows that compared with the fact that temperature influence parameters,when the temperature does not affect the resistivity and specific heat capacity,the kinetic energy of the armature is greater and the coil temperature rise is smaller,but the difference is smaller.(2)The control equations of electromagnetic field and temperature field in the mathematical model of multi-physical field coupling are introduced.The simulation flow of direct coupling and indirect coupling are also introduced.The electromagnetic-temperature field of a single-stage induction coil transmitter with single pulse discharge is studied by finite element method.The results are compared with the current-wire method.The single pulse discharge temperature measurement experiment of single-stage induction coil transmitter is carried out.The experimental results show that the actual measured current results are basically consistent with the simulated current results.Considering the hysteresis of temperature sensor and the error of sampling frequency,the maximum temperature difference of the coil and the armature between the actual results and the simulated results is 6.1%.(3)The electromagnetic-temperature field of continuous pulse discharge of single-stage induction coil is simulated.The results show that the temperature of armature and coil increases gradually and the resistance increases with the increase of pulse discharge times.At the same energy,the coil and the armature single impulse temperature rise of the continuous pulse discharge decreases with the decrease of the current of the coil and the armature.The continuous pulse discharge temperature measurement test of the single-stage coil launcher is carried out,and the test result shows that the actual measurement current result is basically consistent with the simulation current result.Considering the hysteresis of temperature sensor and the error of sampling frequency,the maximum temperature difference of the coil and the armature between the actual results and the simulated results is 9.59%,which verifies the simulation results.(4)Combined with the simulation results of single-stage induction coil launcher temperature field and continuous pulse discharge temperature field and experimental verification,the influence of forced air cooling,different turns and external circuit on the temperature rise of continuous pulse discharge between coil and armature is analyzed.And the temperature test is carried out by simulation for different continuous current circuit.The simulation results are verified.Finally,a temperature control plan of continuous pulse discharge for armature and coil is presented.