Numerical simulation of DC arc characteristics by multiple physical field coupling

Short process electric arc furnace (EAF) steelmaking offers the advantages of high efficiency, low energy consumption, resource circulation, and carbon reduction. To address global climate challenges, short process EAF steelmaking is crucial for optimising the structure of the steel industry and achieving emission reductions. The EAF obtains its primary heat from the high-temperature arc established between the electrodes upon system energisation. Constructing an effective model that captures the arc’s internal mechanisms and the electrical properties of arc plasma is essential for a comprehensive understanding of arc characteristics. In this study, to analyse the arc region of a DC EAF and investigate the temperature distribution and the effects of varying input current and distance between electrodes, a simulation model was constructed based on COMSOL multiphysics software. When the distance between electrodes is 400 mm, as the input current increased from 24 kA to 98 kA the highest temperature of arc increased from 2345 K to 6262 K, resulting in a more uniform arc-column centre temperature and more efficient heat transfer between arc and melt pool. The voltage and current of arc region increased, the conductivity of arc plasma enhanced and equivalent resistance decreased, thereby enhancing arc power intensity. Conversely, when the input current is 24 kA, as the distance of electrodes increased from 400 mm to 700 mm, the highest temperature of arc decreased, with larger distances result in greater temperature reductions. The voltage of arc region increased, while the current of arc region decreased, and conductivity in the arc plasma region kept stable and equivalent resistance increased slightly, arc power intensity occurred a minor decrease. The input current more significantly influences the arc temperature and volt-ampere characteristics than the distance between electrodes. This model provides a theoretical framework for temperature regulation and power supply system optimisation in EAF steelmaking.