Numerical Simulation of Short-Arc-Plasma Characteristics in DC Electrofusion Magnesium Furnaces

To clarify the heat transfer and flow characteristics of arc plasma in a DC magnesium electrofusion furnace under short-arc conditions, a two-dimensional axisymmetric magnetohydrodynamic (MHD) model was developed. Coupled electromagnetic, thermal, and flow fields were solved using COMSOL Multiphysics 6.3, and the model was validated against Bowman's free-arc experimental data. Results show that the arc is electromagnetically constricted into a contracted column, with high-temperature and high-velocity regions concentrated near the arc center. Unlike conventional long arcs, the short arc reaches the anode before the jet fully diffuses, causing momentum to be concentrated on the anode surface and generating pronounced pressure peaks. Higher current increases the arc temperature and jet velocity, thereby strengthening the pressure and shear stresses exerted on the molten pool. In contrast, increasing the arc length reduces the arc temperature, flow velocity, and surface forces, weakening both momentum transfer and heat transfer to the molten pool. Overall analysis reveals that arc length has a more significant effect on arc-molten pool interactions than current and is the dominant parameter governing short-arc behavior. These findings provide guidance for optimizing operating conditions and improving energy utilization in magnesium electrofusion furnaces.