Heat flux to an asymmetric anode in a hot refractory anode vacuum arc

A 3D thermal hot refractory anode vacuum arc (HRAVA) anode problem was developed and numerically solved by the finite-difference method. The heat flux from the plasma to an asymmetric anode with a slanted front surface in a HRAVA was determined using a three-dimensional numerical model for the heat flow in the anode and anode temperature measurements. The effective anode voltage (defined as the total heat flux to the anode divided by the arc current) was ∼7.0-7.5 V for the range of gaps and arc currents 5-18 mm and 125-225 A, respectively. The effective anode voltage increases slightly (∼2-3%) with the arc current increasing from 125 to 225 A. The effective anode voltage decreases (∼6-7%) with gap distance increasing from 5 to 18 mm. The heat flux to the asymmetric anode was strongly asymmetric with the maximum at the anode apex. The calculated heat flux density at the apex was up to 3 times higher than at the anti-apex.