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3860 |
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Thursday, May 22, 2014, Hall H3 9:00 AM Modeling & Simulation 1 |
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Numerical modeling of arc dynamics in a conventional DC plasma spray torch |
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Armelle Vardelle* / University of Limoges-CNRS, France Maher Alaya / University of Limoges CNRS, France Christophe Chazelas/ University of Limoges CNRS, France Gilles Mariaux/ University of Limoges CNRS , France |
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The plasma torch is the basis of the plasma spray process and understanding the electric arc dynamics and plasma generation within the plasma torch should allow a better control of process instabilities and coating reproducibility. Numerical simulation is a useful tools for investigating the effect of the torch geometry and operating parameters on the electric arc characteristics provided that the model of arc dynamics is reliable and that the conditions imposed over the boundaries of the computational domain are well founded. However even if various works in the literature deal with the modelling of DC non-transferred arc plasma torch, such a model is still challenging as it should address the intricate transient and 3-D interactions of the dynamics of the electrically conducting fluid and electromagnetic, thermal and acoustics phenomena. Especially, the description of the electrode regions where the electric arc connects with the solid material and the arc reattachment process, i.e. the formation of a new arc attachment on the anode wall, are important parts of a realistic model of the plasma torch operation. This paper describes the 3-D and time-dependent numerical simulation of a plasma arc and is focussed on the extent of the computational domain and the imposed boundary conditions. In particular, the model is used to investigate the differences in arc characteristics when the solid electrodes and the outflow region are included into the numerical domain. |