Three-Dimensional Non-equilibrium Modeling on the Characteristics of the Dual-Jet Direct-Current Arc Plasmas

Abstract

In this paper, the three-dimensional (3-D) two-temperature modeling on the characteristics of the dual-jet DC arc argon plasmas under different plasma working gas flow rates ranging from 0 to 15 slpm or the chamber pressures increasing from 0.4 to 1.0 atm are conducted at a fixed arc current of 80 A. The modeling results reveal a significant 3-D feature of the temperature and flow fields of the plasma arc-jet due to the declination of the electrodes to each other geometrically, and an obvious deviation from the local thermodynamic equilibrium (LTE) state resulting from the interactions between the high temperature plasma and the cold walls or cold surrounding gas. With other parameters being unchanged, the spatial distributions of the LTE plasma region changed significantly with increasing the plasma working gas flow rate; and the decrease of the chamber pressure leads to the expansion of the high-temperature region and the shrink of the LTE plasma region, which shows a more significant non-LTE feature of the plasma arc-jet. The calculated heavy-particle temperature distributions and the arc voltages are qualitatively consistent with the experimental measurements.