Two-Temperature Modeling of the Anode Contraction Region of High-Intensity Arcs

In this paper, an analytical model for a two-temperature plasma (Te > Tg) is established which is suitable for dealing with arcflow interactions induced by the arc itself. This model is applied to the anode contraction region of high-intensity argon arcs taking the interaction of anode and cathode jets close to the anode into account. The complete set of conservation equations describing the mass, charge, momentum, and energy transport of a two-temperature plasma with temperature-dependent transport properties is solved numerically by an interative finite-difference method using appropriate boundary conditions. Results for an atmospheric-pressure argon arc indicate that the temperature discrepancy between electrons and heavy particles is very pronounced in the arc fringes and in the regions close to the anode, while the departure from kinetic equilibrium becomes insignificant in regions in which the temperature exceeds 12 000 K (i.e., in the arc core). The computed temperature fields of the heavy particles in the anode contraction region resemble the observed arc appearance which clearly shows the interaction of anode and cathode jets in front of the anode.