アルゴンGTAにおける非平衡プラズマ特性の電流値依存性

Abstract

Gas Tungsten Arc (GTA) is suitable as a heat source device for many applications because it can stabilize high temperature arc plasma easily by employing shielding gas. In many cases, (Magneto Hydro Dynamic) MHD simulation model assuming the local thermodynamic equilibrium (LTE) is utilized for analyzing property of GTA. Although the LTE assumption is effective to evaluate high temperature region in the arc column, it is difficult to apply it to low temperature region such as the fringe of the arc column or the sheath regions closed to the electrodes due to decrease of energy exchange caused by collisions. Especially, in order to consider the influence of chemical reaction between the arc plasma and the material surface such as oxidation, non-equilibrium property of the arc plasma should be considered without the LTE assumption, since it is required to understand precise property of the arc plasma closed to the material surface. We have developed a simulation model of GTA assuming chemical and thermal non-equilibrium. In this paper, as a first step of the study, heat source property of argon GTA employing a water-cooled copper anode was simulated and dependence of non-equilibrium plasma property on argon GTA on arc current was investigated.