Measurement of the temperature of a pulsating electric arc discharge

A simple method for determining the temperature on the axis of an oscillating arc column is proposed.Campinas University, Gleb Vatagin Institute of Physics, Brazil. Translated from Inzhenerno-Fizicheskii Zhurnal, Vol. 66, No. 6, pp. 707–709, June, 1994.     

Velocity of the electric arc in a plasmatron discharge chamber

An experimental investigation of the velocity of a high-current arc with air injection in the discharge chamber of a coaxial sectioned plasmatron is described. The experiments showed that the velocity of the cathode spot on the electrode surface depends on the arc current and on the external magnetic field strength. The air flow rate in the plasmatron chamber was 7.1 g/sec.Translated from Inzhenerno-Fizicheskii Zhurnal, Vol. 17, No. 3, pp. 570–574, September, 1969.     

An axisymmetric electric discharge as a means for remote heating of gas and for ignition of combustible gas mixture

Experimental and theoretical investigations are performed of gasdynamic phenomena accompanying a ring electric discharge excited in air at atmospheric pressure. It is experimentally demonstrated that the discharge generates a toroidal (three-dimensional) shock wave which cumulatively converges toward the axis. A mathematical model is constructed, which describes the process of focusing of the toroidal shock wave. The results of measurements of shock-wave processes accompanying the discharge are in good agreement with the calculation results; this enables one to estimate the gas temperature which may be attained in the region of cumulative convergence at some distance from the ring center. Results are given of first experiments in the excitation of a ring shock wave in a combustible gas mixture (stoichiometric mixture of CH₄:O₂).     

Spectral properties of a diffuse-constricted arc discharge

An extensive high-current electric discharge under atmospheric pressure is characterized by considerable instability, unless special measures for its stabilization are assumed (e.g., by the walls, electrodes, rotational twist, etc.). For the experimental investigation of such a discharge, both the complex diagnostics of electrical and spectral properties have been applied, supplemented with synchronous video filming of the discharge gap. The information on the spectral composition of the radiation of different discharge sections can be obtained by measuring with a system of optical fibers. Spectral measurements at the selected point of space at various moments of time make it possible to determine the alteration dynamics of plasma composition near the reference spots, as well as far from them.     

Physical investigations of a high-current vacuum arc discharge

The experimental data on the processes at the electrodes and in the interelectrode gap of a high-current vacuum arc discharge that were accumulated by different researchers are systematized. A critical analysis is conducted on the essentially static discharge models proposed earlier. A dynamic model of a two-component plasma is described and substantiated, which, in the opinion of the authors, better explains the current results of experimental studies into this type of electric discharge than the static models.Translated from Inzhernerno-Fizicheskii Zhurnal, Vol. 62, No. 5, pp. 733–738, May, 1992.     

Utilization of electric arc furnace dust as a solid catalyst in biodiesel production

Clean Technologies and Environmental Policy - World’s energy sources like petrochemical oils, natural gas and coal cause global warming and environmental pollution. Therefore, the traditional...     

Generation of a metal porous film by arc discharge

The copper wire vaporization method is applied to obtain porous copper film on a silicon surface. We determine the distribution of the surface clusters over the sizes and the density. The average size of the clusters under optimal conditions (at a distance of 2 mm from the discharge) is about 0.5 μm, and the deposition density is 3–5 clusters per squared μm.     

Plasmachemical synthesis of coatings using a vacuum arc discharge

In this paper we discuss the issues of applying protective coatings on the copper anodes of powerful generator tubes. As a synthesized material due to its high operational properties was chosen titanium carbide obtained by sputtering a titanium cathode in benzene vapors. Scheme of a vacuum arc device used in this work and also the technological processes for the plasmachemical synthesis of coatings on complex shape anodes are described. For a correct choice of the technological parameters it was considered a model of penetration of the plasma flux into the hollow copper anode that was verified by experiments using a setup with a variable cavity diameter. On the emission spectrum of the discharge in the process of coating deposition shown in this work were recorded spectral lines corresponding to the atoms and ions of titanium and carbon ions. We investigated the distribution of elements across the thickness of the formed coating immediately after deposition and after annealing in vacuum, also the X‐ray diffraction pattern and a microsection for the obtained titanium carbide coating are presented. As a result of the work it can be noted that the described sequence of technological processes, subject to the control of plasma flux parameters, allows obtaining a high quality protective coating on parts of complex shape.     

A turbulent electric arc in a submerged jet

We have experimentally investigated the optical and electrical characteristics of a turbulent electric arc burning at the axis of a submerged jet.Translated from Inzheherno-Fizicheskii Zhurnal, Vol. 57, No. 4, pp. 533–538, October, 1989.     

Interaction of plasma jets in a two-jet electric arc

The interaction of plasma jets in a two-jet electric arc was analyzed based on the results of the numerical solution of magnetogasdynamic equations in a plane parallel approximation of an equilibrium plasma. The role of the mass, heat, and charge transfer processes in the formation of the calculated two-jet arc structure has been established which qualitatively agrees with the experimentally observed properties.     

Experimental study of heat transfer in an electric arc gas heater with vortex stabilization of the discharge

The results of an experimental investigation into heat transfer in the discharge chamber of an electric-arc gas heater are presented. For the anode the resultant data are expressed in the form of generalized relationships q_an=f(I, d), St=f(l/d, Re, N/GH₀). The energy losses in the basic arc spot are estimated.Translated from Inzhenerno-Fizicheskii Zhurnal, Vol. 20, No. 1, pp. 76–81, January, 1971.     

Synthesis of polyhedral graphite in a forced flow arc discharge

Polyhedral graphite (PG) particles have been synthesized by DC arc vaporization of pure graphite in He and H₂ gases with a fan blowing across the arc zone. The crystal structure and character of PG particles have been investigated by transmission electron microscopy, X-ray powder diffraction, and Raman scattering spectroscopy. The PG particles produced by arc discharge, ranging in diameter from 70 to 300 nm, have a turbostratic structure and have no hollow cavities in their centers. The yield of PG particles is about 50%. The cooling rate increase of carbon vapor caused by the forced flow plays a significant role for PG formation.     

Coral-like amorphous carbon nanotubes synthesized by a modified arc discharge

A coral-like amorphous carbon nanotube was prepared by a modified arc discharging furnace in hydrogen atmosphere with a mixture of Mo-Co₂O₃-Mg powders as catalyst at 600°C. This carbon nanotube presented a microscopic coral-like by SEM observation and amorphous structure of nanotubes by HRTEM observation. The XRD diffraction and Raman pattern presented noncrystal characteristics compared to the normal graphite structure. We believed that these results may be affected by the “synergistic” effect of catalyst, atmosphere, and temperature in the synthesis process. The possible explanations to the formation mechanism of this novel carbon nanotube have also been proposed.     

Numerical simulation of the spatial structure of a moving arc discharge

Results are given of the calculation of the structure of an arc discharge moving on parallel electrodes in air under the effect of a transverse magnetic field (0.086 T) at a current strength of 320 A. The numerical simulation is performed within an unsteady-state three-dimensional mathematical model of radiation magnetogasdynamics. The calculations reveal that fluctuations of values of physical parameters and of spatial shape of arc arise in the arc, which are caused by the gas flow past the discharge column and by unsteady-state processes in the electrode regions. Comparison is made with the available experimental data.     

Calculation of electric arc interaction with a turbulent gas flow

The characteristics of an electric arc in a turbulent gas flow are studied. Relationships for calculating turbulent transport are presented.Translated from Inzhenerno-Fizicheskii Zhurnal, Vol. 54, No. 4, pp. 550–557, April, 1988.     

An electric arc in a channel bearing a turbulent gas flow

A study of the positive column in an arc in a tube containing a turbulent gas flow is presented. Working formulas are given for estimating the arc parameters.Translated from Inzhenerno-Fizicheskii Zhurnal, Vol. 35, No. 1, pp. 113–120, July, 1978.     

Experimental investigations into electric discharge grinding and ultrasonic vibration-assisted electric discharge grinding of Inconel 601

The paper presents experimental investigations into electric discharge grinding (EDG) and ultrasonic vibration-assisted electric discharge grinding (UVAEDG) of Inconel 601. The process parameters selected for both processes were duty cycle, discharge current, pulse on time, grinding wheel speed, work speed, and speed ratio to study their influence on responses like surface roughness (R_a) and material removal rate (MRR). It was found that duty cycle, wheel speed, work speed, discharge current, speed ratio, and pulse duration significantly influenced MRR and R_a. It was inferred that MRR increased with increase in duty cycle, wheel speed, current, work speed, and pulse duration in both EDG and UVAEDG processes. It was also inferred that R_a increased with rise in duty factor, pulse on time, and discharge current in EDG and UVAEDG processes.     

Optimization of the heating of a metal by an electric arc

We investigate and generalize the results of experimental measurements of heat fluxes in a metal anode from a plasma jet of a plasmatron with an external arc (PEA) whose operating conditions vary over a wide range.Notation efficiency of heating of the metal - Q_el heat flux into the calorimeter - I current of the electric arc - U voltage drop across the electric arc - V linear velocity of rotation of the sensor - r_o thermal radius of arc spot - _o time until surface of calorimeter begins to melt - t_p melting point of copper - t_o initial temperature of calorimeter surface - q specific heat flux in the heating spot - a thermal diffusivity - D diameter of rotating calorimeter - t₁ temperature of surrounding medium - t₂ temperature of the surface of the rotating calorimeter - G argon flow rate - h_s specific enthalpy of argon in the region near the anode - h_a specific enthalpy of argon at the surface of the calorimeter - k Boltzmann constant - T_e electron temperature in the anode region - e charge of the electron - U_a potential drop at the anode - _a work function of electrons leaving copper - L length of open part of the arc—distance from the cut in the nozzle of the PEA to the sensor - h depth of cathode insertion into the nozzle—distance from the cut in the PEA nozzle to the cathode - d diameter of the PEA nozzle - U _a ^* effective voltage equivalent Translated from Inzhenerno-Fizicheskii Zhurnal, Vol. 39, No. 4, pp. 687–691, October, 1980.     

Flow turbulence in a cylindrical channel encompassing an electric arc

The effect of an electric arc on the gas flow in a cylindrical channel is investigated. It is shown that the striking of an arc in a laminar flow leads to its turbulence at the boundary of the arc column. Within the arc column, the flow is rendered laminar by the high viscosity of the arc plasma. However, thermal turbulence may develop in the central part of the arc.Academic Scientific Combine A. V. Lykov institute of Heat and Mass Exchange, Academy of Sciences of Belarus', Minsk. Translated from Inzhenerno-Fizicheski Zhurnal, Vol. 62, No. 4, pp. 601–607, April, 1992.