Simulation and experimental research on air arc motion in low-voltage circuit breaker

The mathematical model of 3-dimentional air arc plasma under the effect of external magnetic field is set up based on magnetic hydro-dynamics (MHD). Considering the characteristics of anode and cathode, reasonable current density distributions are imposed and a method related to natural electrical conductivity of the arc plasma is used to determine the arc root position. By adopting the commercial computational fluid dynamics (CFD) package based on control-volume method, the above MHD model is solved and verified using images recorded by a high-speed camera. The characteristics of the motion of the arc plasma are described, and the propagation and reflection of pressure wave are considered as the reason of motion in arc chamber. In addition, double-vortices induced by cathode jetting and the 'tail' at the back of the arc plasma are described in detail.