Research On Rock Fragmentation By The Effect Of High Voltage Pulse Discharge Plasma

The mechanism of high pressure pulse plasma rock breaking is that water and other dielectric can produce a variety of physical changes under the condition of high pressure pulse discharge,and the high energy and high density plasma shock wave produced by this process has great impact force.Since the experts of the former Soviet Union discovered this technology,it has become a research hotspot in many fields.High voltage pulse plasma rock breaking system is mainly composed of high power pulse device,plasma electrode,dielectric and related mechanical structure.As a new type of rock breaking method,it has the advantages of high crushing efficiency,small energy consumption of crushed rock,no environmental pollution and so on.The application of high voltage pulsed plasma in ore mining has been gradually studied abroad,but there are some problems such as low rock breaking efficiency,poor crushing effect and unstable system;In the study of high pressure pulsed plasma rock surface,the whole discharge energy is small,the volume of broken rock is small,and the equipment is relatively rough.It is in the experimental stage of theoretical research.In this paper,a high pressure pulsed plasma rock breaking system is designed and constructed by using the principle of impulse force produced by high voltage pulsed plasma.A new type of plasma electrode was designed,and the foam dielectric and water were selected as the dielectric.The parameters of the high voltage pulse discharge circuit were modeled and analyzed.The high power pulse device was selected and the crushing experiment on the strong rock was completed.By analyzing the basic principle of high voltage pulse plasma discharge rock breaking,the plasma electrode and related mechanical structure are designed and modeled,and the finite element simulation analysis of the main force components of the electrode is carried out.A new type of plasma electrode and related mechanical structure with 55 mm diameter and 60 k V withstand voltage were designed.Innovative research on the application of foam dielectric,according to different dielectric ionization characteristics of two kinds of yin and Yang dielectrics,the two kinds of foam is simple,no pollution to the environment.Secondly,the change of impact pressure under different dielectric conditions is calculated.The bubble dynamic equation is used to analyze and calculate the movement state of bubbles in the discharge process.The physical model of electrical detonating wire resistance and the electrical formula are constructed to derive differential equations of each discharge stage.Through the MATLAB numerical analysis software,the influence of the circuit inductance,resistance,wire properties and other parameters on the current waveform is analyzed,which provides the theoretical basis for the optimization of discharge parameters.In this paper,the high power pulse discharge device,which meets the requirements of the experiment,is selected.The maximum discharge voltage can reach 60 k V,the capacitance is 1280 mu F,which has a specific control system and good reliability.A set of high pressure pulsed plasma rock breaking system has been built through the design,processing and selection of related rock breaking devices.Through the experiment,it is proved that the plasma rock fragmentation is relatively less than the other rocks in the explosive and no fly rocks,no smoke,and so on.It has successfully broken the large volume of concrete,basalt and granite.