Numerical study of the anode boundary layer in atmospheric pressure arc discharges

Semenov, Igor; Krivtsun, I.V.; Reisgen, Uwe

doi:10.1088/0022-3727/49/10/105204

Cited by 42 publications

(36 citation statements)

References 40 publications

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“…However, such uni…ed modelling is highly computationally intense in the case of arc plasmas, where the charge particle density is very high, space-charge sheaths occupy only a tiny fraction of the computation domain, and the separation of charges in the bulk plasma is very small. Up to now this approach has been applied only to one-dimensional (1D) models of near-cathode and near-anode regions which separate the electrodes from the bulk of the arc where local thermodynamic equilibrium (LTE) holds [13][14][15].…”

Section: Uni…ed Modellingmentioning

confidence: 99%

“…A variant of the approach employing the LTE description of the bulk plasma was considered in [41,42]. Another variant of this approach can in principle be developed on the basis of simulations [13][14][15].…”

Section: Other Possible Approachesmentioning

confidence: 99%

“…The rest of this work is concerned with comparing characteristics of cathodic part of arc discharges computed by means of three approaches: the uni…ed modelling, the NLTEsheath approach, and the model of nonlinear surface heating. Since the uni…ed modelling has been performed until now only in 1D cases [13][14][15], while the NLTE-sheath approach has been realized only for the 2D (axially symmetric) case [28], all the three approaches cannot be compared at once. In this section, we compare the uni…ed modelling and the model of nonlinear surface heating.…”

Section: Other Possible Approachesmentioning

confidence: 99%

“…If the solid represents an electrode and its surface is hot enough, there is a second group of electrons in the sheath: those emitted by the electrode surface. Therefore, in the general case one can write J (pl) ew = J CD j em =e; (15) where j em is the density of electron emission current. Integral balance of electron energy in the sheath reads j em e 2kT (s) J CD 2kT (pl) e + q (pl) ew J (pl) ew eU sh = 0:…”

Section: Acknowledgmentsmentioning

confidence: 99%

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Account of near-cathode sheath in numerical models of high-pressure arc discharges

Benilov¹,

Almeida²,

Baeva³

et al. 2016

J. Phys. D: Appl. Phys.

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Three approaches to description of separation of charges in near-cathode regions of high-pressure arc discharges are compared. The …rst approach employs a single set of equations, including the Poisson equation, in the whole interelectrode gap. The second approach employs a fully non-equilibrium description of the quasi-neutral bulk plasma, complemented with a newly developed description of the space-charge sheaths. The third, and the simplest, approach exploits the fact that a signi…cant power is deposited by the arc power supply into the near-cathode plasma layer, which allows one to simulate the plasma-cathode interaction in the …rst approximation independently of processes in the bulk plasma. It is found that results given by the di¤erent models are in a generally good agreement, and in some cases the agreement is even surprisingly good. It follows that the predicted integral characteristics of the plasma-cathode interaction are not strongly a¤ected by details of the model provided that the basic physics is right.

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Section: Uni…ed Modellingmentioning

confidence: 99%

Section: Other Possible Approachesmentioning

confidence: 99%

Section: Other Possible Approachesmentioning

confidence: 99%

Section: Acknowledgmentsmentioning

confidence: 99%

See 2 more Smart Citations

Account of near-cathode sheath in numerical models of high-pressure arc discharges

Benilov¹,

Almeida²,

Baeva³

et al. 2016

J. Phys. D: Appl. Phys.

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“…Though arcs has been extensively studied earlier, most of the studies considered only specific aspects of the arc physics: cathodic region 7,8,9,10,11,12,13 , arc column 14,15 , anodic region 16,17,18,19,20,21,22,23,24 . A detailed review of works on argon arc modeling can be found in Ref.…”

Section: Introductionmentioning

confidence: 99%

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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Numerical study of the anode boundary layer in atmospheric pressure arc discharges

Cited by 42 publications

References 40 publications

Account of near-cathode sheath in numerical models of high-pressure arc discharges

Account of near-cathode sheath in numerical models of high-pressure arc discharges

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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