Effect of arc model assumptions on the prediction of anode erosion

A large body of experimental and theoretical literature deals with the electrode erosion phenomena in high power electric arcs. For the anode, they have showed that they mainly depend on the arc current density, electrode temperature, time of residence of the arc, nature of the plasma gas and fluid dynamics behavior of the plasma inside the torch. If these studies help to better understand the erosion phenomena, they have to consider the actual torch geometry and operating conditions for practical use in plasma torch design. Two key issues are the dimensions of the anode arc root and its displacement on the anode wall. Numerical models of arc behavior that couple the electrodes and the fluid could address these issues. However, the dimensions of the arc attachment are affected by the assumptions of the model that can make it to change from diffuse to constricted. This study tackles this problem; it compares the anode attachment predicted by a LTE and a 2-Temperature arc model and discusses the repercussion on anode erosion.