Thermal and Chemical Nonequilibrium Effects in Free-Burning Arcs

Baeva, M.

doi:10.1007/s11090-015-9650-9

Cited by 21 publications

(7 citation statements)

References 66 publications

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“…The interest in the modelling of plasma-electrode interaction in high-pressure arc discharges has signi…cantly increased in the last couple of years [1][2][3][4][5][6][7][8][9][10][11][12]. Models of various levels of complexity have been developed for the plasma-cathode interaction.…”

Section: Introductionmentioning

confidence: 99%

Computing anode heating voltage in high-pressure arc discharges and modelling rod electrodes in dc and ac regimes

Almeida¹,

Cunha²,

Benilov³

2017

J. Phys. D: Appl. Phys.

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Numerical modelling of near-anode layers in arc discharges in several gases (Ar, Xe, and Hg) is performed in a wide range of current densities, anode surface temperatures, and plasma pressures. It is shown that the density of energy ‡ux to the anode is only weakly a¤ected by the anode surface temperature and varies linearly with the current density. This allows one to interpret the results in terms of anode heating voltage (volt equivalent of the heat ‡ux to the anode). The computed data may be useful in di¤erent ways. An example considered in this work concerns the evaluation of thermal regime of anodes in the shape of a thin rod operating in the di¤use mode. Invoking the model of nonlinear surface heating for cathodes, one obtains a simple and free of empirical parameters model of thin rod electrodes applicable to dc and ac high-pressure arcs provided that no anode spots are present. The model is applied to a variety of experiments reported in the literature and a good agreement with the experimental data found.

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Section: Introductionmentioning

confidence: 99%

Computing anode heating voltage in high-pressure arc discharges and modelling rod electrodes in dc and ac regimes

Almeida¹,

Cunha²,

Benilov³

2017

J. Phys. D: Appl. Phys.

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“…Great progress has been achieved in the development and application of kinetic nonequilibrium in thermal plasma flow models. The state-of-the-science is exemplified by the work on arc discharges by Baeva [4], Baeva et al [5], Trelles [88,90] and Baeva [7]; on arc welding by Boselli et al [16,17], Konishi et al [44], Baeva [6] and Nonequilibrium in an arc discharge: Kinetic nonequilibrium is the result of microscopic particle and field imbalances, which lead to deviations from LTE, mass action laws, quasi-neutrality, etc., and is exemplarily observed in the region near the anode. Dissipative nonequilibrium is the result of the existence of multiple solutions in nonlinear systems and the propensity of a system to achieve a configuration that more effectively dissipates energy.…”

Section: Modeling Of Nonequilibrium In Thermal Plasma Flowsmentioning

confidence: 99%

Nonequilibrium Phenomena in (Quasi-)thermal Plasma Flows

Trelles

2019

Plasma Chem Plasma Process

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Thermal plasmas are utilized in diverse applications that require high power densities or throughputs, such as metal cutting, welding, spraying, metallurgy, and materials synthesis. Thermal plasma applications involve interactions between the highly energetic plasma and working gas streams, confining devices, or processing materials. Whereas thermal plasma implies a state of equilibrium (i.e. Local Thermodynamic Equilibrium, LTE), due to the above interactions, thermal plasma flows depict nonequilibrium phenomena of two types: kinetic and dissipative. Kinetic nonequilibrium manifests microscopically and is caused by localized imbalances between particles and fields interactions. Its occurrence is evidenced, for example, as deviations from thermal equilibrium between heavy-species and electrons or from mass-action laws. In contrast, dissipative nonequilibrium reveals macroscopically and is produced by external driving forces that incite distributed responses, such as the growth of instabilities, the occurrence of self-organization, or the establishment of turbulence. Although kinetic nonequilibrium has been increasingly incorporated in thermal plasma flow models (e.g. finite-rate chemistry, two-temperature models), it is the great advances in numerical computing that is enabling the exploration of dissipative nonequilibrium (e.g. pattern formation, small-scale turbulent features). Both types of nonequilibrium are reviewed, including their estimation and incidence, within the context of computational models and their relevance to thermal plasma sources and processes.

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“…The collisional-radiative model use several input parameters determined by MHD model from [2,3]. In present contribution the electron and gas temperature, as well as of the electron density obtained from the simulations of a TIG arc in argon are used.…”

Section: Description Of the Modelmentioning

confidence: 99%

“…In general, the description of plasma chemistry requires application of collisional-radiative models. In recent papers devoted to studies of the free-burning Ar arc [1][2][3] a self-consistent two-temperature fluid model with accounting for non-equilibrium effects was presented. The modelling approach is based on the solution of the Navier-Stokes equations for mass, energy, and momentum conservation along with the equations of electric continuity, Ohm's and Ampere's law, which self-consistently determine electric and self-induced magnetic plasma fields.…”

Section: Introductionmentioning

confidence: 99%

“…The inclusion of radiation transport equations in the balance equations for individual particles in the frames of such description is a very challenging task. Therefore, the models [1][2][3] use effective lifetime approximation in order to take into account the corresponding radiation trapping. In the work [4], which used the input data from model [2], a matrix method for description of resonance radiation transport was proposed.…”

Section: Introductionmentioning

confidence: 99%

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Influence of Resonance Radiation Transport on Chemical Equilibrium in an Argon Arc

Gortschakow

Kalanov

Golubovskiǐ

2019

PPT

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<p class="Default">Deviations from chemical equilibrium in argon arc plasma are analysed by means of collisional-radiative model. Corresponding comprehensive kinetic scheme has been developed and applied form study of free-burning arc at the conditions typical for welding applications. While the natural lifetime have been used for radiation emitted from highly excited argon states, the resonance radiation was described taking into account the radiation transport eﬀects. Resulting spatial distributions of excited argon atoms are compared for the cases of LTE and two-temperature plasma using diﬀerent approaches for the description of the resonance radiation transport.<br /><br /></p>

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Thermal and Chemical Nonequilibrium Effects in Free-Burning Arcs

Cited by 21 publications

References 66 publications

Computing anode heating voltage in high-pressure arc discharges and modelling rod electrodes in dc and ac regimes

Computing anode heating voltage in high-pressure arc discharges and modelling rod electrodes in dc and ac regimes

Nonequilibrium Phenomena in (Quasi-)thermal Plasma Flows

Influence of Resonance Radiation Transport on Chemical Equilibrium in an Argon Arc

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