Numerical And Experimental Investigation On The Electrical Explosion Of Metal Wire

With the further development of pulsed power technology,the investigation on the characteristics of exploding wires has been widely and deeply studied.In this paper,the experimental setup of wire explosion is built.The experiments of exploding wires are carried out,and the simplified magnetohydrodynamic model and the equation of state are constructed to carry out the numerical simulation and analysis of electrical explosion of aluminum wire.The experimental setup of wire electric explosion consists of pulsed power generator,trigger module and vacuum system.The power supply circuit mainly includes primary side circuit and secondary side circuit.The primary side circuit includes energy storage capacitor,vacuum trigger switch and pulsed transformer.The secondary side circuit includes secondary energy storage capacitor,self-breakdown switch and vacuum chamber.A coaxial structure of secondary side storage capacitor,self-breakdown switch and vacuum chamber is applied to reduce the inductance of the circuit.By adjusting the distance between the two electrodes of the self-breakdown switch and the pressure of charging gas,the magnitude rising rate of pulsed current can be adjusted.The trigger circuit is used to provide a trigger signal for the vacuum trigger switch.The amplitude of the trigger pulse is ?20k V,and the rise time of the pulse is ?40?s.In order to explore the exploding characteristics of electrical explosion of metal wire in vacuum environment,a vacuum system is needed to extract the gas in the vacuum chamber.In order to describe the physical process of wire electric explosion,a physical mathematical model is established to simulate the process of wire electric explosion.According to the state of exploding products,the process of wire explosion can be subdivided into four stages: I.solid state stage;II.wire melting stage;III.wire complete melting and initial plasma formation stage;IV.core-corona structure development stage.Thermodynamic model is used to calculate the temperature rise and energy deposition of the wire under the action of pulsed current in the I and II stages prior to the complete melting of the wire.In stage III,one-dimensional magnetohydrodynamic model is used to calculate the radial distribution of the exploding products,while in stage IV,a simplified magnetohydrodynamic model is used to describe the evolution process of the core-corona structure.The relationship between pressure,specific volume and temperature is required in the physical mathematical model,thus,the equation of state is constructed.The phase transition of aluminum is obtained,and the equation of state and the transport parameter model which can describe the phase transition process of metal wire from solid state to plasma,are applied in the simplified magnetohydrodynamic model.Through the physical mathematical model,the numerical simulation is carried out,and the voltage waveform of the electric explosion of aluminum wire is obtained.The variation of resistance,instantaneous power and deposition energy with time in the process of electrical explosion is further analyzed.The numerical simulation results are in relatively good agreement with the experimental results.