This paper mainly focuses on the influence of three kinds of media:air,air-10%PA(Nylon) and air-10% POM (polyoxymethylene) on low-voltage circuit breaker arcs.A three-dimensional (3-D) model of arc motion under the effect of external magnetic field is built basedon magnetohydrodynamics (MHD) equations.By adopting the commercial computational fluiddynamics (CFD) package based on the control-volume method,the above MHD equations aresolved.For the media of air-10%PA and air-10%POM,the distributions of stationary temperatureand electrical potential and the transient motion processes are compared with those of air arc.The research shows that both air-10%PA and air-10% POM can cool the arc plasma and theformer is more-effective.Both of them can increase the stationary voltage as well.Moreover,thepresence of the two mixtures can accelerate the arc motion toward the quenching area and ensuresthe arc quenched in time.
This paper is devoted to the simulation of the arc plasma in a simplified low-voltage circuit breaker chamber. Based on a group of coupled governing equations, a three-dimensional (3-D) arc plasma model is built and solved by a modified commercial code. Firstly, this paper presents a solution of the stationary state of the arc plasma and discusses the distribution of some parameters throughout the chamber. Secondly, with the ferromagnetic materials included,the balance of the stationary state is broken and a transient course is calculated. In light of the simulation results, the temperature distribution sequence, the arc motion and the plasma jet are then described and analyzed in detail.
