Numerical Modeling of Plasma Arc: Inclusion of Electrodes in the Computational Domain

Numerical simulations can be useful tools for investigating the effect of the torch operating parameters and geometry on the arc characteristics and its interactions with electrodes. Up to now, most of the 3-D time dependent models of DC plasma torch are performed without including the solid walls into the computational domain. As a consequence, boundary conditions for the electromagnetic equations are questionable and may affect the discharge characteristics as the arc root size and arc dynamics. Moreover, the heat load to the electrodes, and so electrode erosion, cannot be properly modelled.

 This work deals with a 3-D time-dependent numerical simulation of a plasma arc ; it involves the arc column region and solid electrode regions in the same computational domain. The differences in arc characteristics when the solid electrodes were included or not into the computational domain were investigated for various operating parameters.