MATCHING OF COMPATIBLE WORK OF SHORT HIGH-VOLTAGE PULSES OF TENSION GENERATOR AND WATER TREATMENT CHAMBER BY DINT OF PULSE BARRIER DISCHARGE

A technique for calculating the parameters of a magnetic switch as an element of a generator of short high-voltage pulses of tension to coordinate its compatible work with a water treatment chamber by dint of pulse barrier discharge is shown. The expediency and efficiency of using such a switch as an element that, by shunting, the discharge chamber, discharges the barrier to the arrival of the next voltage pulse has been confirmed. It is proved that with the accepted geometrical dimensions of the discharge chamber and the amplitude of the pulse voltage, provided that the magnetic switch is present that it is possible to increase the practical use of electricity by ~ 40% due to that which was accumulated in the dielectric barrier in one discharge. Ref.10, fig. 5.

Distributed ferromagnetic enhanced inductive plasma source for plasma processing

New experimental data on the plasma density profiles have been obtained for a low-frequency (100 kHz) distributed ferromagnetic enhanced inductive plasma source at different locations of inductive discharges. An ability to control the plasma density profiles in a large gas discharge chamber in order to achieve a uniform treatment of a substrate is demonstrated. The differences between the obtained results and literature data for a distributed ferromagnetic enhanced inductive plasma source combined with a radio-frequency inductive discharge are discussed.

Particle Surface Modification in the Near-Electrode Region of an RF Discharge

The results of a study on particles’ surfaces after being exposed to the near-electrode region of a radio frequency (RF) discharge are presented. It was experimentally displayed that metal starts being deposited on the surface of particles levitating above the lower electrode of the discharge chamber after switching the RF discharge on. For melamine-formaldehyde (MF) particles, the appearance of an island metal coating is observed after 30 min of plasma exposure. Eroded electrodes and elements of the gas discharge chamber may serve as a source of deposited material. In addition, an analysis of the surface and composition of particles placed on the upper electrode after 6 h of plasma exposure is presented. We reveal that the composition and structure of the particle coating changes during the experiment. The MF particles under exposure become eroded, and needle-like structures containing metals are formed on their surface. We also observe the formation of columnar structures from the products of erosion of electrodes on particles with a metal coating.

Uncompleted Fullerenelike Structures: Synthesis and Chracteristics

The literature is considering completely formed fullerenes as usually. Without attentions have been left uncompleted ones, and their properties are practically unknown. Such structures may be received at arc discharge synthesis in the limited space with short time of synthesis. Here synthesis was made at arc discharge chamber with little radius and less gas flow. The time-of-flight mass spectrum synthesized product on m/z size showed containing of hydrated uncompleted-composite fullerene. They were like with structures: C54H4, C56H4, C56H8, C68H4 and other. A presence at mass spectrum of abnormal structures was manifested in form of doublet many-peaks lines. They also confirmed termperature-formating of new bonds with successive griping valence bonds with poliin structures at arc discharge. From mass spectrum, on base of Mendileive’s chemical plate was supposed the way forming conjectural structure. The MS-picture was confirmed with estimation for forming many-peaks abnormal poliin like structures.

Modeling of Processes in Plasma of Radio-Frequency Ion Injector with an Antenna Placed inside the Volume of Discharge Chamber

The work is devoted to the theoretical assessment of the efficiency increase possibility for the radio-frequency ion injector, which is designed for the contactless removal of space debris from near-earth orbit by using an antenna located inside the discharge chamber. Four internal antenna configurations and two external ones—end and side—are considered. Expected characteristics were estimated using an engineering mathematical model built in COMSOL Multiphysics using an approximate magnetohydrodynamic description of the charged particle behavior. According to the simulation results, the best characteristics can be obtained with an internal antenna with a conical arrangement of turns. Calculations showed that in some operating modes, such an antenna configuration makes it possible to halve the radio-frequency power consumption compared to the classical antenna located on the discharge chamber side surface. The performed theoretical study showed that the internal antenna can significantly increase the ion injector efficiency. In the future, verification of the obtained results by test is planned.

Analytical and numerical methods for calculation the deep of penetration the welding seam formed by the electron beam generated by glow discarge electron guns

The article is devoted to the problem of defining the focal diameter of electron beam, formed by the glow discharge electron guns, as well as the necessary pressure in the gun chamber for realising the welding process. Taking into account, that glow discharge electron guns are widely used in industry for welding of different metals, and that for providing the high quality of welding joints estimation of energetic parameters in beam focus is very important, proposed methods are very important for effective elaboration and designing of the novel glow discharge electron guns constructions for specific technological operations. With known focal beam deameter and thermodinamic parameters of welding details material the deep of penetration of welding seam, as well as the necessary pressure in discharge chamber have been estimatied. Two proposed methods are generally based on the analytical solving of explite equation and on numeracal solving of sophisticated non-linear equation. Obtained simulation results with and without taking into account the spsace charge of own beam electrons are also given

Influence of Vapor-Gas Cavity on Pressure Field in Closed Discharge Chamber with Rigid Walls

The pressure field in discharge chambers of a limited volume with deformable walls very often has a great influence on the efficiency of technological processes of deformation of sheet alloys; therefore, its determination is an urgent task. As a result of an electric discharge in the liquid filling the discharge chamber, in it, a cavity with a higher compressibility is formed than the liquid in the chamber. At the stage of the discharge, this cavity is filled with non-ideal plasma, and after the discharge, with liquid vapor and gases dissolved in it (vapor-gas cavity). Its pulsations form a pressure field in the discharge chamber. The moving boundary of the vapor-gas cavity creates great problems in calculating the pressure field in a liquid, especially after a large number of its pulsations. At present, the role of the vapor-gas cavity in the formation of the pressure field in the discharge chamber with a deformable wall, which is a sheet alloy plate, is insufficiently studied. Its definition is the purpose of this work. The study was carried out on the base of a previously developed mathematical model of an electric discharge in water, which in this work is supplemented with relations that significantly increase the accuracy of calculating the resistance of the discharge channel and the energy released in it. It was determined that the pulsations of the vapor-gas cavity provide pressure fluctuations in it in an antiphase with the average pressure in the liquid. In a discharge chamber with rigid walls, they decay slowly, but the presence of a deformable wall leads to a rapid decay of pressure fluctuations. In the previously developed mathematical model, the change in the optical transparency of the plasma was taken into account, and its significant effect on the pressure in the cavity and the pressure field in the liquid was determined.

RESEARCH OF ENERGY EFFICIENCY OF PROCESSING BY PULSE BARRIER DISCHARGE OF WATER IN A DROP-FILM STATE

The energy efficiency of a pulsed barrier discharge in air was investigated when it treated a model water sample in a drop-film state containing an organic dye (methylene blue) with an initial concentration of 50 mg/l. The water consumption was 4 l / min, the characteristic droplet diameter was ~1 mm. Water treatment was carried out in a coaxial discharge chamber with a gas gap of 3.2 mm and additionally in an ozonation chamber. The discharge was generated by short ~ 100 ns voltage pulses of ≈26 kV, which provided a current density with an amplitude of ≈1.3 A/cm2 and a pulse energy of ≈ 140 mJ. The time of decomposition of the impurity and the energy efficiency of the discharge were investigated as a function of the pulse repetition rate of 25−300 Hz. The discharge had the highest energy efficiency at frequencies of 25-50 Hz, at which the energy yield corresponding to 50% decomposition of the impurity is about 100 g/kW h. It is shown that most of ozone, one of the main oxidants generated by the discharge, dissolves in water in the discharge chamber. The concentration of ozone at the outlet from the discharge chamber can reach 2.2 mg/l. The remaining ozone is absorbed by the model solution (about 60%) in the ozonization chamber. References 16, figures 7.