Numerical investigation on the influence of metal particles on the characteristics of a high-current vacuum arc

Abstract

In the arc-burning process of a high-current vacuum arc (HCVA), the metal particles (MPs) splashed from the active anode will have a significant influence on the plasma characteristics of the arc column. In this paper, the influence of varying MPs on the characteristics of HCVA are studied by establishing a HCVA model containing single or multiple MPs. The simulation results show that when the MPs vaporized metal vapor (MV) enters the interelectrode region and once the arc column plasma cannot ionize all atoms immediately, the ionization layer and the neutral atom vapor area (NAVA) will be formed in the adjacent region of the MPs. When the MP diameter and temperature increase, the number of vaporized metal atoms increases, so that the influence range of MV increases, and the area of ionization layer and the NAVA increases. In addition, when the arc current increases or the MPs are closer to the cathode surface, the greater the ion number density and ion pressure around the MPs are, the stronger the compression on the MV will be, resulting in the decrease of the area of ionization layer and the neutral atom vapor, and the increase of the net ionization rate of the ion number density. When multiple MPs exist in the interelectrode region at the same time, the MV from the MPs will affect each other. In the central region of multiple MPs, the density of MV becomes the largest, while the net ionization rate of ion number density is distributed in the periphery region of the MP group.