Simulation and experimental research on air arc movement characteristics in low-voltage circuit breaker considering electrodes erosion

The mathematical model of 3-dimentional arc plasma considering the erosion of electrodes was set up based on magnetic hydro-dynamics (MHD). The Cu vapor mass concentration equation was introduced to the model on the basis of traditional mass, momentum and energy equations. The influence of electrodes erosion on the thermodynamic and transport properties was considered. The arc-cathode model and arc-anode model were built aiming at the difference of cathode and anode. By adopting the commercial computational fluid dynamics (CFD) package based on control-volume method, the above MHD model was solved and the distribution of temperature field, concentration field, flow field and electrical potential field in the arc chamber were calculated. The simulation results indicate that the maximal Cu vapor concentration locates at the region behind the arc root because of the existence of 'double vortex' near electrodes. The simulated arc voltage considering the influence of Cu vapor is 12.3% lower than the result without considering the influence of Cu vapor. The simulated arc average speed considering the influence of Cu vapor is 21.3% lower than the result without considering the influence of Cu vapor. The experimental results prove the validity of the arc model.