A simplified unified theory of arcs and their electrodes

Lowke, J. J.; Morrow, R.; Haidar, J

doi:10.1088/0022-3727/30/14/011

Cited by 236 publications

(235 citation statements)

References 33 publications

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“…In the first publications, devoted to mathematical simulation of the processes of heat, mass and charge transfer in refractory cathode arcs [2][3][4][5][6][7][8][9][10], arc plasma was assumed to be single-component, i.e. containing atoms and ions of just the shielding gas.…”

mentioning

confidence: 99%

Simulation of electric arc with refractory cathode and evaporating anode

Krikent¹,

Krivtsun²,

Demchenko³

2014

The Paton Welding J.

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Equation of convective diffusion of ionized metal vapour in arc plasma, allowing for the difference in coefficients of diffusion of atoms, single-and double-charged metal ions, presence of thermodiffusion flows of metal particles, as well as ion drift in the electric field, was proposed to more precisely define the earlier developed complex model of the processes of energy, mass and charge transfer in the column and anode region of electric arc with refractory cathode and evaporating anode, running in inert gas. Based on the thus precised complex mathematical model, numerical analysis of the influence of diffusion-induced evaporation of anode material (Fe) on heat, gas-dynamic and electromagnetic characteristics of multicomponent plasma of the column and anode region of stationary electric arc with refractory cathode (W) at its running in inert gas (Ar) was performed. An essential influence of metal surface temperature distribution in the region of anode binding of the arc on distribution of temperature and electric current density in near-anode plasma, as well as on distributed and integral characteristics of its thermal impact on evaporating anode surface, is shown. 18 Ref., 12 Figures. K e y w o r d s : electric arc, refractory cathode, evaporating anode, arc column, anode region, multicomponent plasma, metal vapour, diffusion, mathematical simulationElectric arc plasma in inert-gas nonconsumableelectrode welding, as a rule, is multicomponent, as alongside shielding gas particles, it contains atoms and ions of metal vapour coming to the arc gap due to evaporation of anode metal from weld pool surface. Presence of an even small amount of metal component in inert gas arc plasma has an essential influence on its ionization composition, thermodynamic, transport and optical properties. It leads to a significant difference of heat, electromagnetic and gas-dynamic characteristics of plasma in near-anode zone of arc column in nonconsumable-electrode welding from respective characteristics of arc discharge with refractory cathode and nonevaporating, for instance, water-cooled anode. Characteristics of welding arc anode region, determining the conditions of thermal and electromagnetic interaction of the arc with metal being welded and, consequently, nature of its penetration, are also different [1].In the first publications, devoted to mathematical simulation of the processes of heat, mass and charge transfer in refractory cathode arcs [2-10], arc plasma was assumed to be single-component, i.e. containing atoms and ions of just the shielding gas. Such idealization did not incorporate any conditions of running of real welding arcs, and required further improvement of mathematical models of the arc, in order to allow for a number of additional physical factors, related to multicomponent nature of arc plasma. Publications devoted to allowing for evaporation of anode material in simulation of nonconsumableelectrode welding arc, appeared in the world scientific literature comparatively recently [11][12][13]. When describing...

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mentioning

confidence: 99%

Simulation of electric arc with refractory cathode and evaporating anode

Krikent¹,

Krivtsun²,

Demchenko³

2014

The Paton Welding J.

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“…Anodic and cathodic sheaths have been neglected, while electrodes interfaces are taken into account using a simplified approach, imposing a current density distribution on the cathode surface. Neglecting sheath phenomena allows reducing the computational effort since their influence on the main body of the arcs is negligible as shown in [12]. In all the performed calculations, the required database of equilibrium and non equilibrium thermodynamic and transport properties has been taken from [13].…”

Section: Model Descriptionmentioning

confidence: 99%

3D static and time-dependent modelling of a dc transferred arc twin torch system

Colombo¹,

Ghedini²,

Boselli³

et al. 2011

J. Phys. D: Appl. Phys.

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HAL is a multi-disciplinary open access archive for the deposit and dissemination of scientific research documents, whether they are published or not. The documents may come from teaching and research institutions in France or abroad, or from public or private research centers. L'archive ouverte pluridisciplinaire HAL, est destinée au dépôt et à la diffusion de documents scientifiques de niveau recherche, publiés ou non, émanant des établissements d'enseignement et de recherche français ou étrangers, des laboratoires publics ou privés.3D static and time-dependent modelling of a dc transferred arc twin torch systemTo cite this version: Abstract. The transferred arc plasma torch device consists of two electrodes generating a plasma arc sustained by means of an electric current flowing through the body of the discharge. Modeling works investigating of transferred electric arc discharges generated between two suspended metallic electrodes, in the so called twin torch configuration, are scarce. The discharge generated by this particular plasma source configuration is characterized by a complex shape and fluid dynamics and needs a 3D description in order to be realistically predicted. The extended discharge length that goes from the tungsten pencil cathode to the flat copper anode without any particular confinement wall and the fluid dynamics and magnetic forces acting on the arc may induce an unsteady behavior. In order to capture the dynamic behavior of a twin torch discharge, a 3D time dependent plasma arc model has been developed using a customized commercial code FLUENT form in both Local Thermodynamic Equilibrium (LTE) and non-LTE. A two temperature (2T) model has been developed taking into account only the thermal non-equilibrium effects in argon plasma. The main differences between LTE and 2T models results concern the increased extension of the horizontal section of the discharge and the predicted reduced (of about 60-80V) voltage drop between the electrodes when using a 2T model.

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“…In the eighties and nineties some authors (for example [1][2]) proposed to calculate the self-induced magnetic field by using the equation:…”

Section: -Maxwell Ampere Equationmentioning

confidence: 99%

“…Chronologically, the first formulation, in the eighties, was the Maxwell -Ampere (M.A.) form which has been used in two-dimensional (2D) modelling in numerous articles such as Hsu [1] or Lowke [2]. It is very convenient in 2D on a structured grid but not really suited to an unstructured one.…”

Section: Introductionmentioning

confidence: 99%

Magnetic field approaches in dc thermal plasma modelling

Freton¹,

Gonzalez²,

Masquère³

et al. 2011

J. Phys. D: Appl. Phys.

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The self-induced magnetic field has an important role in thermal plasma configurations generated by electric arcs as it generates velocity through Lorentz forces. In the models a good representation of the magnetic field is thus necessary. Several approaches exist to calculate the self-induced magnetic field such as the Maxwell–Ampere formulation, the vector potential approach combined with different kinds of boundary conditions or the Biot & Savart (B&S) formulation. The calculation of the self-induced magnetic field is alone a difficult problem and only few papers of the thermal plasma community speak on this subject. In this study different approaches with different boundary conditions are applied on two geometries to compare the methods and their limitations. The calculation time is also one of the criteria for the choice of the method and a compromise must be found between method precision and computation time. The study shows the importance of the current carrying path representation in the electrode on the deduced magnetic field. The best compromise consists of using the B&S formulation on the walls and/or edges of the calculation domain to determine the boundary conditions and to solve the vector potential in a 2D system. This approach provides results identical to those obtained using the B&S formulation over the entire domain but with a considerable decrease in calculation time.

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A simplified unified theory of arcs and their electrodes

Cited by 236 publications

References 33 publications

Simulation of electric arc with refractory cathode and evaporating anode

Simulation of electric arc with refractory cathode and evaporating anode

3D static and time-dependent modelling of a dc transferred arc twin torch system

Magnetic field approaches in dc thermal plasma modelling

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