In MHD approximation, a mathematical model of spark discharge in liquid nitrogen is worked out on the basis of data generalization pertaining to thermodynamical functions and mass-transfer coefficients in a wide parameter range. The results obtained are used for analysis of both integral and spatial-temporal discharge characteristics important for practical application.

In order to ensure electromagnetic noise immunity of pulse power equipment intended for increasing oil and artesian well output production the quantitative determination of the level of electromagnetic interference generated by high voltage discharges, places of their origin and ways of distribution has been carried out in the article. The design of the installation, its location in the borehole and the ways of current spreading along the installation hull through the medium that fills the borehole have been analyzed. The effect of both components of the total current, i.e. of the conduction current and the displacement current, on the values and characteristics of the electric field distribution in the studied system of objects, including the pulsed power installation, the liquid medium filling the borehole and the well casing has been determined. On the basis of the analysis performed the equivalent circuit of the system has been worked out, the parameters of its elements have been determined with accounting for the skin effect in the installation hull, the mathematical set of equations has been worked out to determine the level of electromagnetic interference. The uneven distribution of the electric potential amplitude values along the installation hull length at every moment, high pulse values of the electric potential within the location of electronic means controlling the pulse power equipment, whose dependence on time reproduces the shape of the electric discharge current, a significant effect of the specific conductivity of the liquid in the well on the distribution of electrical potential have been obtained with numerical solution of the mathematical model. On the base of the performed numerical analysis the reliability of the pulse power equipment operation has been significantly improved by shielding the hull, which was not continuous in the area of the cable entry, and separation of zero point of the high-voltage charging device with an intermediate frequency conversion from the installation hull.

The numerical simulation of a spark discharge formed along the axis of a cylindrical chamber filled with water has been carried out in the magnetohydrodynamic approximation. The simulation results are compared with the data known from the literature. The analysis of the spatiotemporal distribution of the pressure and temperature in the discharge chamber has been performed with due account for the interaction between the shock waves excited by the spark discharge and reflected from the chamber’s wall and the plasma channel.

A continuous and nonwaste process is proposed that consists of a set of simultaneous operations concerning the electrodischarge treatment of carbon liquid in reactors through exposure to high temperatures and pressures generated by a plasma discharge channel, the selection and separation of the processed sub-stance in filtering or centrifugal separating devices, and the recirculation of the purified material in a closed hydraulic system. The product, depending on the method used for the selection and separation, is a thick pasty mass or a dry powder mixture containing various modifications of carbon: fullerenes, nanotubes, and nanodiamonds (up to 10% of the total weight). A prototype of the electric equipment has been built to provide processing performance of from 0.02 to 1.5 kg/hour. It has a maximum installed capacity of 5 kV A, and the specific energy consumption ranges from 0.1 to 10 MJ/kg. The surge-current generator with microprocessor control was designed for industrial applications. It allows achieving the maximum discharge pulse recurrence frequency of 200 Hz, which is limited by the time of the medium’s relaxation and the dielectric strength’s restoration in the discharge gap. This ensures the versatile regulation and a shift in the corresponding processing performance of the single-reactor systems in the range from 0.4 to 30 kg/hour. This technology is complemented with the developed method for the enrichment of the produced ultrafine powder. It consists of an original sequence of physical and chemical methods (magnetic separation, acid treatment, chromatographic purification, etc.) and can increase the targeted selectivity of the processed products.

Numerical simulation of high power air spark discharge characteristics in a circuit with an inductive-capacitive energy store and a foil blasting release has been carried out with a magneto-hydrodynamic approach application. Influence of the discharge circuit parameters (the plasma channel length, voltage of the plasma load connection to the discharge circuit, inductor store inductance) on the spark characteristics has been determined.

Influence of electroblasting breaker parameters (switch inductance, foil length and width) on electric spark discharge characteristics in a circuit with an inductive-capacitive energy store and plasma load is studied by means of numerical simulation in magnetohydrodynamical approximation.

In the approach of magnetic hydrodynamics a closed set of equations that represents a mathematical model is worked out. Analysis of spatial and temporal transient characteristics of underwater spark discharge is conducted. The results of numerical simulation are compared with results of the known experimintal investigations.

Taking into account a set of initial electron generation mechanisms, applicability of a numerical method for breakdown probability characteristics calculation is widened for high- voltage apparatus gaseous insulation with high values of electric field strength (> 5 MV center dot m(-1)). The characteristics of gaseous insulation in real compact designs of a low- inductance high- voltage gaseous switch and a submegavolt pulse voltage generator have been calculated with the method.

A specialized economical algorithm for numerical analysis of capacitor storage charging in charging circuits with semiconductor frequency converters is introduced. The approach is accurate enough real-world applications, allows avoiding bulky difference schemes used in solving stiff sets of differential equations. With the method, charging calculation time is reduced by a 100-to-1000 factor for capacitor storages of high capacitance.

High values of pressure and temperature can be achieved under electric discharges in liquids. It explains the interest in their widespread application both in physical experiments on pulsed power and industry. Wide-range quantitative information on these phenomena was analyzed and systematized at the IPRE due to theoretical and experimental investigations carried out during last years. The aim of this paper is to estimate some investigation results obtained at the IPRE as well as the achievements in pulsed power industrial application.

Equipment for creation electrical discharges in liquids finds application for well stimulation in the process of oil or water production by restoring permeability of the well hole-bottom region affected during operation by the deposition of asphalt, resinous substances or mechanical impurities, breaking and removing a colmatant from the bore-hole walls, as well as by formation fracturing to increase permeability of the hole-bottom regions. Some attention to this problem is paid previously, where the results of application of the devices created at the IPRE in the oilfields of Ukraine, Russia and China are generalized. This paper is intended to show the progress pertaining to design and fabrication of the equipment for oil and water well stimulation.

Computer simulation of electrical discharges in the high-pressure chambers of electrothermal launcher pulsed power supply systems containing homopolar generators (HPGs), storage inductors (SIs) and two-stage opening switches with mechanical and explosive circuit breakers has been carried out at the chamber radii of (0.02-0.1) m and various values of the gap spacing (0.1-0.8) m. Space-time dependences of pressure and temperature in the chambers as well as energy losses in the circuit elements are calculated. Up to 40 per cent of the HPG energy is shown to be delivered to the plasma load. Taking it into account, the volume and the mass of a transportable power supply providing the energy input to the load at the level of 5 MJ and consisting of two 6.5 MJ HPGs connected in parallel, a 9 MJ SI, a rotating mechanical circuit breaker as well as an explosive one operating due to the current conducting thin metal cylinder destruction by annular cumulative jets are evaluated. Simulation results of the medium heating and pressure oscillations in the chamber operating at the currents of 200-300 kA through each HPG and energies of 100-300 kJ per shot are presented.

Summary form only given. At present, considerable attention is paid to investigation of the influence of liquid environment conditions on electrical discharge processes. This interest can be explained by the necessity of pulsed power facilities operation under conditions which are substantially far from normal. This paper presents the results of experimental and theoretical study of the influence of initial conditions on the underwater discharge development at high pressure and temperature. An experimental study of the electrical discharge in water with specific conductivity of 6.4/spl times/10/sup -2/ Sm/spl middot/m/sup -1/ was carried out at the hydrostatic pressure values ranged from 0.1 MPa to 50 MPa. Measurements of the discharge current, gap voltage as well photographing of the plasma channel development by high speed camera with framing speed of 1 million frames per second were carried out during the experiment. Up to 15 shots were done for every set of parameters with the consequent statistical treatment of the obtained data.

Summary form only given. High values of pressure and temperature can be achieved under electrical discharges in liquids. This explains the interest in their widespread application both in physical experiments on pulsed power and in industry. A wide-range of quantitative information on these phenomena was analysed and systematized at the Institute of Pulse Research and Engineering due to investigations carried out during the last few years. The aims of this paper are to determine the main trends of R&D in the field of numerical simulation of electrical discharges in liquids, to show the achieved results, and to expose some new problems for electrical discharge modeling.

In this paper investigation results that have been carried out to explain the influence of the compact closing switch parameters on the electric field strength distribution and the breakdown probability taking into account the electrode surface roughness and nonuniform electric field are presented. The dependencies of the breakdown probability as functions of the gap voltage have been determined at various electrode shapes, characteristics of surface roughness and different values of the compact switch inner diameter. The results obtained allow improvement upon the compact closing switch by choosing the appropriate correlation of its parameters.

Breakdown in water with high electric conductivity has been investigated with the use of an electrode unit which allows formation of layers of low specific conductivity water around the high-potential electrode point. The influence of the layer parameters on the electric field strength distribution and breakdown development has been studied with numerical simulation and experimental methods of oscillography and optical registration. The electric field strength increase and reduction of the breakdown time is shown to be obtained in the electrode unit proposed.

In this paper, the results of numerical simulation of high-current discharges in pulsed plasma generators with inductive energy storage are presented. In one case, the circuits with capacitor banks, storage inductors and aluminum fuses for switching 100-300 kA currents into plasma loads have been considered. In the other case, discharges in facilities containing compact homopolar generators, energy storage inductors in conjunction with two-stage (mechanical and explosive) opening switches to generate output pulses in plasma channels with 10-20 /spl mu/s risetime and currents of 200-300 kA are analyzed. An approach to numerical simulation is described. The results obtained allow to agree the parameters of the pulsed generators with plasma load characteristics and evaluate the pulsed plasma generators operating efficiency.