Abstract
In this work, the authors present results from a computational multiphysics model for direct-current plasma arcs operating in open bath electric smelting furnaces. Plasma thermodynamic and thermophysical properties of a range of mixtures of hydrogen and water vapour that might be expected in the gas space of a smelter using pure hydrogen as a reductant are discussed, with most properties seen to be strong functions of the plasma temperature and composition. The properties are combined with the multiphysics model and used to generate predictions of the arc behaviour, with both quasi-steady state and fully transient simulations conducted. The electrical performance of the arc was found to be highly dependent on the hydrogen:water ratio in the freeboard gas, with larger hydrogen fractions causing the arc to become less stable and more electrically resistive.