Investigation of the short argon arc with hot anode. II. Analytical model

Khrabry, Alexander; Kaganovich, Igor; Nemchinsky, Valerian; Khodak, Andrei

doi:10.1063/1.5007084

Cited by 33 publications

(35 citation statements)

References 28 publications

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“…[42] by comparison to the results of previous numerical studies [41] and in Ref. 43 by comparison to analytical solutions. Convective-diffusive transport of atomic carbon in the helium atmosphere was solved yielding a profile of carbon atoms density in the arcing volume and surrounding areas.…”

Section: Arc Modelmentioning

confidence: 84%

Synthesis of nanoparticles in carbon arc: measurements and modeling

et al. 2018

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This work studies the region of nanoparticle growth in atmospheric pressure carbon arc.Detection of the nanoparticles is realized via the planar laser induced incandescence (PLII) approach.Measurements revealed large clouds of nanoparticles in the arc periphery, bordering the region with high density of diatomic carbon molecules. Two-dimensional computational fluid dynamic simulations of the arc combined with thermodynamic modeling explain these results due to interplay of the condensation of carbon molecular species and the convection flow pattern. The results have shown that the nanoparticles are formed in the colder, outside regions of the arc and described the parameters necessary for coagulation.

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Section: Arc Modelmentioning

confidence: 84%

Synthesis of nanoparticles in carbon arc: measurements and modeling

et al. 2018

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“…In the previous theoretical studies 7,8,9 conductive heat flux to the cathode was neglected leading to overestimation of the ion current fraction. This question is addressed in more details in the accompanying paper 44 .…”

Section: Discussion Of the Near-cathode Regionmentioning

confidence: 99%

“…In the present study we provide a justification based on the results of simulations of the whole arc. This simplification will be used in the arc model presented in the accompanying paper 44 . Quantitative asymptotic relations for the nearcathode region voltage drop, electron temperature, ion current and for size of the region is presented in the accompanying paper 44 .…”

Section: Discussion Of the Near-cathode Regionmentioning

confidence: 99%

“…The near-anode region is typically longer than the near-cathode region and its length depends more strongly on the current density. Analytical relations for layers with dependence of current density can be found in the accompanying paper 44 . At higher current densities, the equilibrium region occupies significant part of the long arc, but is not observed in the short arc at any of the current densities considered.…”

Section: Iv2 Parametric Studies Of Argon Arcmentioning

confidence: 99%

“…Hence, the parameter P is small compared with unity throughout the arc, including major parts of the near-electrode regions. This statement will be used in the analytical arc model presented in the accompanying paper 44 .…”

Section:   mentioning

confidence: 99%

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Investigation of the short argon arc with hot anode. I. Numerical simulations of non-equilibrium effects in the near-electrode regions

et al. 2018

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Atmospheric pressure arcs have recently found application in the production of nanoparticles. Distinguishing features of such arcs are small length and hot ablating anode characterized by intensive electron emission and radiation from its surface. We performed one-dimensional modeling of argon arc, which shows that near-electrode effects of thermal and ionization non-equilibrium play important role in operation of a short arc, because the non-equilibrium regions are up to several millimeters long and are comparable with the arc length. The near-anode region is typically longer than the near-cathode region and its length depends more strongly on the current density. The model was extensively verified and validated against previous simulation results and experimental data. Volt-Ampere characteristic (VAC) of the near-anode region depends on the anode cooling mechanism. The anode voltage is negative. In case of strong anode cooling (water-cooled anode) when anode is cold, temperature and plasma density gradients increase with current density resulting in decrease of the anode voltage (absolute value increases). Falling VAC of the near-anode region suggests the arc constriction near the anode. Without anode cooling, the anode temperature increases significantly with current density, leading to drastic increase in the thermionic emission current from the anode. Correspondingly, the anode voltage increases to suppress the emission -and the opposite trend in the VAC is observed. The results of simulations were found to be independent of sheath model used: collisional (fluid) or collisionless model gave the same plasma profiles for both near-anode and near-cathode regions.Parametric studies of short atmospheric pressure argon arc with tungsten electrodes were performed for various current densities and inter-electrode gap sizes. Non-equilibrium effects in the near-electrode regions were studied. Anodes with and without water cooling were considered. Effect of electron emission on current-voltage characteristic of the near-anode layer was investigated. Analytical formulas for scaling of non-equilibrium regions widths and Volt-Ampere's characteristics of these regions and the whole arc are given in the accompanying paper 44 .The organization of the paper is as follows. In Section II governing equations and boundary conditions for plasma and electrodes are presented. Section III describes numerical procedure of solving the governing equations. Results of simulations including validation of the model and parametric studies of the arc are presented and discussed in Section IV. Conclusions of this work are summarized in Section V.

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Plasma parameters of microarcs towards minuscule discharge gap

Baeva

Loffhagen

Becker

et al. 2020

Contributions to Plasma Physics

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This paper describes the behaviour of the plasma parameters of microarcs generated between a cooled copper anode and a ceriated tungsten cathode by means of a one-dimensional unified non-equilibrium model for gap lengths between 15 and 200 μm and current densities from 2 × 10 5 up to 10 6 A/m 2. The results obtained show that the decrease of the gap length to a few tens of micrometres for a given current density results in a progressive shrinking of the quasi-neutral bulk in the microplasma and its complete disappearance. The decrease of the gap length further leads to an increase of the discharge voltage and the electron temperature and to slightly less heating of the gas.

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Investigation of the short argon arc with hot anode. II. Analytical model

Cited by 33 publications

References 28 publications

Synthesis of nanoparticles in carbon arc: measurements and modeling

Synthesis of nanoparticles in carbon arc: measurements and modeling

Investigation of the short argon arc with hot anode. I. Numerical simulations of non-equilibrium effects in the near-electrode regions

Plasma parameters of microarcs towards minuscule discharge gap

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