MHD modeling of rotating arc under restrike mode in ‘Kvaerner-type’ torch: part I. Dynamics at 1 bar pressure
Résumé
This paper focuses on the 3D MHD modeling of an arc plasma at industrial level; the torch is a 'Kvaerner-type' one, made of two concentric graphite electrodes and where spots are displaced with an external magnetic field. Different phenomenologies in arc movement were observed, ranging from a gliding arc on electrodes surfaces to hopping arc foots, agreeing with previous experimental works at atmospheric pressure. These dynamics have non-negligible consequences in the plasma process: the hopping mode induces more erosion due to a higher heat flux at the electrodes surfaces in comparison to the gliding arc; the latter mode results also in a strong gas swirling inside the torch, thus longer particles residence time is predicted.