Simulation and experiment on airarc characteristics in low-voltage circuit breaker considering wall ablation

The mathematical model of 3-dimentional air arc plasma considering the ablation of lateral walls is set up based on magnetic hydro-dynamics (MHD). The mass concentration equation is introduced to the model on the basis of traditional mass, momentum and energy equations. The influence of wall ablation on the thermodynamic and transport properties is considered. The method of "view factors" is used to calculate the radiation reaching the lateral wall. By adopting the commercial computational fluid dynamics (CFD) package based on control-volume method, the above MHD model is solved and the distribution of temperature field, concentration field, flow field and electrical potential field in the arc chamber is calculated. The simulation results indicate that the vapor concentration behind the arc column is higher than that in front of the arc column because of the existence of "vortex" in the arc chamber. The use of gassing material causes arc voltage increase 19.2%, and causes the average arc velocity increase 20.1%. The experimental results prove the validity of the arc model.