Parametric study of plasma torch operation using a MHD model coupling the arc and electrodes

A key issue in the modeling of non-transferred arc plasma torch is the electromagnetic coupling between the electric arc and electrodes. At the cathode tip, it is generally based on a current density profile imposed on the cathode surface. However, it is delicate to predetermine this profile as experimental observation cannot be done. To get rid of this boundary condition, the solution is to include the electrodes in the computational domain, impose the arc current on the rear surface of the cathode and solve the electromagnetism equations and energy conservation both in the fluid and electrodes. This solution has been recently implemented in a CFD computer code.

This study uses the model under various plasma torch operating conditions to validate the predictions obtained with this novel approach. Such a model can be then applied with confidence to cascaded-anode plasma torches.