Numerical simulation of vacuum arc based on an improved MHD model

During the arc interruption process of vacuum circuit breakers (VCBs), the behavior of inter-electrode plasma, which has a great influence on the anode progress and further impacts the electric insulation recovery speed of VCBs, is a the key factor determining the interruption performance of VCBs. In this paper, according to the actual flowing status of vacuum arc, based on the previous two-temperature MHD model, we firstly presented an improved Magneto Hydro Dynamic (MHD) model including the standard k-ε turbulence equations and it is suitable to simulate both of the supersonic arc and subsonic arc. Then the multi-physics coupling software-COMSOL was adopted to simulate the high-current supersonic arc and subsonic arc existing in some typical commercial VCBs. After that, the spatial distributions of several important plasma parameters of supersonic and subsonic arc, such as density, ion and electron temperature, pressure and Mach number, were calculated and analyzed in detail. Finally, we obtained the distribution of energy flux density on anode surface (EFD), an important parameter which characterizes the specific influence of inter-electrode plasma on the anode status. The numerical simulation results are a great supplement with regards to the experimental results of vacuum arc and the calculated EFD could be used as a heat flux boundary condition for the analysis of anode thermal process.