Analysis of magnetic field formulation for transferred arc thermal plasma modelling

Abstract Thermal plasma modelling of arc plasma systems offers an efficient way to understand the arc dynamics inside the torch and the plume characteristics. Extensive usage of these plasma models necessitates the efforts to improve its fidelity to simulate the actual arc environment. Since the arc dynamics is highly influenced by the self-induced magnetic field, the choice of magnetic field formulations incorporated in the plasma model plays a crucial role. Existing magnetic field formulations based on Ampere’s law, referred as potential vector formulation (PVF), and Biot–Savart law lack accuracy and computational efficiency, respectively. Integration of Biot–Savart law with PVF, referred as mixed formulation (MF), improves the accuracy but still lack computational efficiency. Extended domain based magnetic field formulation (EDF) has the tendency to offer both accuracy and computational efficiency but rarely incorporated in arc plasma system simulations. The present work studies the influence of different magnetic formulations on the self-induced magnetic field prediction in a 2.6 kW transferred arc plasma system. It is inferred that EDF predicts the magnetic field close to that of MF in most of the regions when compared to PVF. Analysing the effect of predicted magnetic field by different formulations on plasma characteristics revealed minimal influence in the considered transferred arc plasma system due to the static arc behaviour. The incorporation of EDF is expected to have significant importance on the scenario with transient arc behaviour.