Simulation of Surface Erosion of Anode under High-current Vacuum Arcs

The anode melting and erosion process has a significant effect on the interruption of a high-current vacuum arc. The objective of this paper is to theoretically investigate the mechanism of anode surface erosion caused by a combined effect of vacuum arc heating and the blow effect of arc pressure. A model of fluid flow and heat transfer of an anode region in a vacuum interrupter's high-current interruption process is developed. The results show that, under the combined effect of arc heating and arc pressure, an obvious erosion on anode surfaces was seen for peak arcing current of 20 kA. The flow of liquid metal started after 5 ms of arcing, the maximum velocity was 0.95 m/s. This flow of liquid metal on anode surfaces driven by arc plasma may redistribute the thermal energy of molten liquid metal. As a result, the maximum temperature of an anode surface did not stay in the center of an anode surface.