Abstract
In order to understand the plasma cutting process for improving the reliability for stable cutting with a prolonged lifetime, the whole region of oxygen plasma jet, namely, a hafnium electrode as a cathode buried in the water-cooled copper sheath, an arc plasma and a copper nozzle as an anode is treated in a unified numerical model. Calculations are made for the two-dimensional distributions of temperature and fluid flow velocity in the whole region of the oxygen plasma jet for a 400 A in arc current. The current density distribution and also the whole energy balance at the tip of cathode and water-cooled copper sheath are predicted. It is shown that the nozzle diameter strongly affects the plasma jet properties and also the nozzle lifetime but weakly affects the hafnium cathode lifetime.
