Numerical Study of Plasma–Electrode Interaction During Arc Discharge in a DC Plasma Torch

Liang, Peng; Groll, Rodion

doi:10.1109/tps.2017.2786079

Cited by 28 publications

(35 citation statements)

References 33 publications

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“…However, questions may rise about the effect of these assumptions on the arc root shape and its motion when it subjected to an external axial magnetic field (Ref 34). Therefore, to get rid of this questioning, the work in progress deals with the implementation of a NLTE model (Ref [35][36][37][38]. Also, the use of plasma-forming gas mixtures of argon and hydrogen is under consideration but this requires to have the nonequilibrium thermodynamic and transport properties of the gas mixtures.…”

Section: Discussionmentioning

confidence: 99%

Control of the Arc Motion in DC Plasma Spray Torch with a Cascaded Anode

et al. 2019

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Two common concerns in DC plasma torches are stability of plasma jet and anode erosion. The challenge is how to get a stable plasma jet with minimal anode erosion. This study tackles this question by using either a swirling gas injection or an external axial magnetic field applied to the Oerlikon SinplexPro™ plasma torch. A 3-D, time-dependent MHD model of the plasma torch operation was used to predict the value of the external magnetic field and its effect on the heat flux to the anode and plasma jet stability. The special feature of the model is to couple the gas phase and electrodes that makes it possible to follow the anode temperature evolution. For specific operation conditions (anode of Ø9 mm, 500 A, Ar 60 NLPM) the model predicted that the maximal value of the azimuthal self-magnetic field inducted by the arc current was 0.055 T; it also showed that an external magnetic field of 0.05 T to 0.1 T could make it possible to limit the anode erosion without noticeably disturbing the plasma jet issuing from the plasma torch. We expect this approach to help to better understand the arc behavior in commercial plasma torches and control anode erosion.

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Section: Discussionmentioning

confidence: 99%

Control of the Arc Motion in DC Plasma Spray Torch with a Cascaded Anode

et al. 2019

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“…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. This is depicted by the formation of patterned anode attachments with increasing cooling, schematically shown by a bifurcation diagram Liang [48]; on ICP sources by Watanabe et al [96] and Tanaka et al [85,86]; and on arc torches by Trelles et al [87], Trelles [89], Alaya et al [3] and Liang and Groll [47].…”

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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“…Three-dimensional and time-dependent models enable the description of the restrike mode of arc attachment on the anode (Ref 2). Nonequilibrium models account for the interaction of the plasma with the cold gas and deviations from equilibrium (thermal and/or chemical) in the arc plasma (Ref 5,6).…”

Section: Introductionmentioning

confidence: 99%

Self-Consistent Cathode–Plasma Coupling and Role of the Fluid Flow Approach in Torch Modeling

et al. 2021

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A two-dimensional and stationary magnetohydrodynamic model of a plasma spray torch operated with argon is developed to predict the plasma properties in a steady operating mode. The model couples a submodel of a refractory cathode and its non-equilibrium boundary layer to a submodel of the plasma in local thermodynamic equilibrium in a self-consistent manner. The Navier–Stokes equations for a laminar and compressible flow are solved in terms of low and high Mach number numerical approaches. The results show that the Mach number can reach values close to one. Simulations are performed for electric currents of 600 A and 800 A, and gas flow rates of 40, 60, and 80 NLPM. The plasma parameters obtained by the two approaches differ, and the differences become more pronounced for higher currents and gas flow rates. The arc voltage, the electric power, and the thermal efficiency from both the low and high Mach number models of the plasma agree well with experimental findings for a current of 600 A and a flow rate of 40 NLPM. For higher currents and gas flow rates, the results of the low and high Mach number models gradually differ and underline the greater appropriateness of the high Mach number model.

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Numerical Study of Plasma–Electrode Interaction During Arc Discharge in a DC Plasma Torch

Cited by 28 publications

References 33 publications

Control of the Arc Motion in DC Plasma Spray Torch with a Cascaded Anode

Control of the Arc Motion in DC Plasma Spray Torch with a Cascaded Anode

Nonequilibrium Phenomena in (Quasi-)thermal Plasma Flows

Self-Consistent Cathode–Plasma Coupling and Role of the Fluid Flow Approach in Torch Modeling

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