Simulation of the development of arc plasma on the solid-liquid interface during high-speed gliding electrical contact

Linear propulsion electromagnetic energy equipment can drive armature to obtain extremely high speed ($\gt 2 \mathrm{~km} / \mathrm{s}$) in a very short time (milliseconds), through the mega-ampere level high current, the acceleration is in tens of thousands of g, and the pressure at the interface can reach hundreds of MPa. High current, high speed and high pressure lead to violent variation in interface behavior, thereby causing rail damage, including: edge groove erosion, center erosion, gauge and transition. There are two main triggers for the phenomenon: liquefaction layer and arc. Arcing can occur both at the beginning and during the armature movement, depending on the contact performance. In order to achieve effective control of the amount of rail wear, it is necessary to avoid the occurrence of arc ablation. In this paper, based on the three-dimensional simulation model of the coupling of electromagnetic field, fluid flow and temperature field, the arc plasma development process of the solid-liquid interface is simulated, and the arc induced by the current density concentration caused by the actual contact area of the interface and the diffusion of the magnetic field after the initial loading of the current is simulated, as well as the arc caused by the velocity skin effect during the ultra-high-speed motion process. The development process of monofilament arc and multifilament arc was simulated respectively, and the method of inhibiting ablation transition was simulated and verified.