Design Of Wire Electrical Explosion Control System And Study On The Effects Of Electrical Parameters

Nanoparticles have special properties such as small size effect,surface effect,quantum size effect and so on,and broad application prospects in military defense,industrial manufacturing,biomedicine and other fields.The preparation of metal nanoparticles by wire electrical explosion has the advantages of convenient adjustment of process parameters,environmental friendliness,uniform distribution and high purit y of the produced nanoparticles.It is expected to become an effective method for industrialized preparation of nanoparticles.The wire electrical explosion system co nsists of the equipment and control system of wire electrical explosion.Aiming at the problems of complex wiring and difficult function modification in relay-based control system,a wire electrical explosion control system based on programmable logic cont roller(PLC)is designed.According to the work flow of wire electrical explosion equipment,the control target was determined.Combining with the characteristics of relevant control devices,the control circuit o f wire electrical explosion control system and the corresponding internal programming logic of PLC were designed.The wire electrical explosion system could automatically and continuously complete the preparation of nanoparticles through the actual wiring.The key link of the wire electrical explosion control system is to control pulse trigger switch to effectively and duly turn on and off the discharging circuit of wire electrical explosion.Aiming at the problems that trigger tube is not reliable enough fo r on-off control of circuit and has influence on current waveform,a pulse trigger switch based on oil medium transfer and its trigger control device are developed.When the metal wire is detected at the right place,the trigger control device controls the oil flow out of the oil-filled space and the switch the switch is turned o n due to gas breakdown,after the wire electric explosion,the trigger control device controls the oil flow back and the switch is turned off due to insulation,the whole process co uld realize effective on-off control of discharge circuit,and the reliability of the trigger switch has been verified theoretically by simulation.In the process of preparing nanoparticles by wire electrical explosion,when the electrical parameters match the quality of the wire,the total deposited energy can fully initiate the explosion of wire and avoid the formation of large particles.In this paper,the effects of electrical parameters on wire electrical explosion process were studied by means of circuit simulation and experiment.In the circuit simulation,a wire model based on specific action was established,current waveforms under different conditions could be obtained by changing electrical parameters,t he simulation results show that,increasing voltage,decreasing inductance,decreasing resistance and increasing capacitance could increase discharge current,and then increase the energy deposition of the wire.In the experimental study,the electrode type and air gap lengths were changed to carry out the wire electrical explosion experiment,which connected the electrical parameters and the design of wire electric explosion equipment.And the deposited energy of the wire can be effectively controlled by the wire electrical explosion system.Current signals with high amplitude and high frequency existed in the wire electrical explosion experiment.The characteristics of current time domain,frequency domain and deposited energy were studied.The results show that,the wire electrical explosion process with high amplitude and high frequency current could completely vaporize the wire and successfully prepare metal nanoparticles.Changing the type o f electrode and the length of air gap not only changes the electrical parameters in the discharge circuit,but also affects the low frequency and high frequency components deposited energy of the wire.It has reference significance for controlling the average particle size of nanoparticles prepared by wire electrical explosion and improving the equipment of wire electrical explosion.