Heat transfer to a cathode of a rotating arc

Nemchinsky, Valerian

doi:10.1088/0963-0252/24/3/035013

Cited by 7 publications

(6 citation statements)

References 26 publications

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“…The idea that Ohm's law should be included in the near-cathode layer modeling, which leads to cathode voltage drop variation along the cathode surface, is not new. This idea has been developed in a series of works by Nemchinsky [3,46,[50][51][52][53]. The basic assumptions for each layer introduced are summarized in table 1.…”

Section: Concept Of the Coupling Methodsmentioning

confidence: 99%

Thermal and electrical influences from bulk plasma in cathode heating modeling

Tang

Wang

Zhang

et al. 2016

Plasma Sources Sci. Technol.

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In this paper, a numerical calculation is performed for the purpose of estimating the thermal and electrical influences from bulk plasma in cathode heating modeling, in other words researching the necessity of a coupling bulk plasma in near-cathode layer modeling. The proposed model applied in the present work is an improved one from previous work.In this model, the near-cathode region is divided into two parts: the sheath and the ionization layer. The Schottky effect at the cathode surface is considered based on the analytic solution of a 1D sheath model. It is noted that the arc column is calculated simultaneously in the near-cathode region and the cathode bulk. An application is presented for an atmospheric free burning argon arc with arc currents of 50 A-600 A.The modeling results show three interesting points: (1) at the cathode surface, energy transport due to heat conduction of heavy particles and electrons is comparable to total heating flux, no matter whether the arc discharge is performed in a high (400 A) or low current (50 A) situation; (2) the electrical influence from bulk plasma on the cathode heating modeling becomes obvious in a high current situation (>400 A) for the spot mode; (3) the near-cathode layer voltage drop (U tot ) is larger in the diffuse mode than in the spot mode for the same current, which is just the opposite to that for decoupled modeling.

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Section: Concept Of the Coupling Methodsmentioning

confidence: 99%

Thermal and electrical influences from bulk plasma in cathode heating modeling

Tang

Wang

Zhang

et al. 2016

Plasma Sources Sci. Technol.

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“…Cathode phenomena have been traditionally considered for deter mining existence of arc plasma discharge and were thought to be more complicated. Therefore, much research [6][7][8][9][10][11][12][13][14][15][16][17][18][19][20] has focused on the nearcathode plasma layer while less attention has been paid to the nearanode plasma layers in the past. However, with the increase of basic research and application of anodes in recent years, it was found that the physics of nearanode plasma layers is no less interesting and complex than that of nearcathode plasma layers [21][22][23].…”

Section: Introductionmentioning

confidence: 99%

Non-equilibrium modelling of free-burning argon arc in different anode sheath regimes

Sun¹,

Wang²,

Zhang³

et al. 2019

J. Phys. D: Appl. Phys.

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In this paper, an anode sheath model coupled with twodimension arc column model is performed to study the physical process in the nearanode region. In the anode sheath model, two different physical mechanisms of ion and electron dynamics, for positive and negative anode sheath voltages, are considered. The effect of the arc column on the anode is also considered. The arc column model accounts for the thermal nonequilibrium and ionization nonequilibrium. The diffusion equations and generalized Ohm's law are used to analyze the effect of diffusion of plasma species near the anode region. The simulation results from this model are presented for an atmospheric freeburning argon arc with arc currents of 50 A and 150 A. The simulation shows that: (1) both positive and negative anode sheath voltages are obtained for I = 50 and 150 A. The distributions of electric potential in front of the anode surface predicted by the model are in good agreement with the experimental data. (2) In the negative anode sheath regime, the diffusion current density exceeds the total current density, which makes the electric field reverse in front of anode surface. In the positive anode sheath regime, the diffusion current becomes negative in the nearanode region, which makes the ohmic current increase rapidly in the nearanode region. (3) There is a significant interaction, which is positive feedback, between the diffusion current and anode sheath voltage in both positive and negative anode sheath modes. (4) The thermal conduction from the arc column plays a major role in the heat transfer to the anode for the negative anode sheath mode while it becomes much smaller for the positive anode sheath mode.

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“…Under this mode, we also noted the importance of the heat prehistory i.e. arc previous locations of the electrodes [54] and consequently on its dynamics. Arc wake represents the cold boundary layer and where the breakdown condition can be satisfied for a future reattachment.…”

Section: Case Studymentioning

confidence: 67%

MHD modeling of rotating arc under restrike mode in ‘Kvaerner-type’ torch: part I. Dynamics at 1 bar pressure

Gueye¹,

Cressault²,

Rohani³

et al. 2019

J. Phys. D: Appl. Phys.

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This paper focuses on the 3D MHD modeling of an arc plasma at industrial level; the torch is a 'Kvaerner-type' one, made of two concentric graphite electrodes and where spots are displaced with an external magnetic field. Different phenomenologies in arc movement were observed, ranging from a gliding arc on electrodes surfaces to hopping arc foots, agreeing with previous experimental works at atmospheric pressure. These dynamics have non-negligible consequences in the plasma process: the hopping mode induces more erosion due to a higher heat flux at the electrodes surfaces in comparison to the gliding arc; the latter mode results also in a strong gas swirling inside the torch, thus longer particles residence time is predicted.

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Heat transfer to a cathode of a rotating arc

Cited by 7 publications

References 26 publications

Thermal and electrical influences from bulk plasma in cathode heating modeling

Thermal and electrical influences from bulk plasma in cathode heating modeling

Non-equilibrium modelling of free-burning argon arc in different anode sheath regimes

MHD modeling of rotating arc under restrike mode in ‘Kvaerner-type’ torch: part I. Dynamics at 1 bar pressure

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