Vinnikov D. Electrophysical Action of Powerful Underwater Spark Discharge on Substance Treatment Processes

Subject of research: electric discharge processes that occur during the treatment of substances by underwater spark discharges. Research objective: the objective was to improve high-power high-voltage electric discharge plants that are used for the technological treatment process of substances using the underwater spark discharge by varying their electrophysical and technological parameters. Methods of research: the methods of the theory of electric circuits, the theory of electromagnetic fields, gas dynamics and plasma chemistry were used for the numeric simulation. A high-speed video-recording was used during the experimental investigation to watch the development of the gas-vapor cavity and cavitation processes; the oscillography was used to register the current, voltage, pressure and acoustic signals; the X-ray fluorescent method allowed us to define the composition of electrode material; the diffractometry was used to define the composition and the size of particles that were formed during the discharge; the metallography was used to define the metal structure; the spectrophotometry was used to define the concentration of iron and its compounds in the water; the Brunauer, Emmett and Teller method was used to define the specific surface of crushed solid substances and the Williamson-Hall method was used to measure particle sizes. The experimental data were processed using the method of least squares. Theoretical and practical results: a high-power high-voltage electric discharge plant "HYDRA" with the specific energy of up to 1kJ/pls and with the series of reactors was created. Scientific novelty: the dependence of a change in the redox potential on the processes that occur in the gas-vapor cavity was established for the first time by using the inelastic membrane for the electrohydraulic reactor that allowed us to view the gas-vapor cavity as a source of the medium with the negative redox potential and use it to vary the properties of liquid substances in the volumes that are within the cavity size and the processes that occur out of membrane, in particular the cavitation were viewed as those that affect the change of pH value; the push was given to the use of underwater spark discharges for the technologies that are used to change the physical and chemical properties of liquids due to the carrying out of discharges with specific powers of up to 1kJ/pulse in electric non-conducting reactors whose size is not exceeding the volume of vapor-gas cavity and it allowed us to define sufficient power consumption and appropriate parameters of the discharge circuit to perform the fast change in the redox potential in comparison with other methods; the push was also given to the research of a change in the dynamics of gas-vapor cavity due to the carrying out of underwater spark discharges in the system of electrodes of a directional effect and reducing the initial pressure in the liquid and that allowed us to route the gas-vapor cavity in the specified direction with the retention of the expansion and compression processes of it; cavitation processes were intensify and the degassing of liquids was also intensified; the electrohydraulic method of the influence on the smelts that are crystallized in vacuum-arc furnaces due to the transfer of shock action through the impermeable crucible wall was improved and it allowed us to reduce the grain sizes of metal crystals 3 to 10 times. The technology of destruction of glass wares in the water and the rubber in the liquid nitrogen medium was improved due to the change in the process sizes of electrohydraulic reactor and evacuation of it and that enabled an increase in the output of the useful fraction by 10% and 17%, accordingly; the mathematical model of the development of vapor-gas envelope at an early stage of the expansion of high-power high-voltage underwater spark discharge was improved due to taking into consideration the expansion of gas -vapor envelop and evaporation of the water steam that enabled the determination of the amount of active components that are formed during the spark discharge and allowed us to control thermodynamic parameters by varying the parameters of discharge circuit. Level of introduction: It was introduced at the Institute for Plasma Electronics and New Methods of Acceleration of the National Science Center "Kharkov Institute of Physics and Technology"; Institute for the Solid Body Physics, Material Science and Technologies of the National Science Center "Kharkov Institute of Physics and Technology"; Institute of Pulse Processes and Technologies of the National Academy of Ukraine and it is used for the teaching process by the National Technical University "Kharkov Polytechnic Institute". The field of use is the electric engineering branch.