Abstract
Two common concerns in dc plasma torches are stability of plasma jet and anode erosion. The challenge is how to get a stable plasma jet with minimal anode erosion. This study tackles this question by using an external axial magnetic field applied to a cascaded plasma torch. A 3D, time-dependent model of the torch is used to predict the value of the magnetic field and its effect on heat flux to the anode as well as plasma jet stability. The model couples the gas phase and electrodes, making it possible to follow anode temperature evolution. For specific operating conditions, the model predicts an azimuthal self-magnetic field induced by electric arcing and the subsequent effect of an external field on arc attachment and anode wall temperature. This approach is expected to provide a better understanding of arc behavior in dc plasma torches and facilitate the control of anode erosion.
