低压断路器中空气电弧运动的仿真及实验研究

以磁流体动力学(MHD)为基础建立了三维空气电弧等离子体在外部磁场作用下运动时的数学模型。考虑到阴极和阳极各自的特点,提出了更加合理的电流分布边界条件;采用一种与电弧等离子体自身电导率密切相关的方法确定电弧的弧根位置。利用基于有限容积法的商业软件对上述模型进行求解,并利用高速数字摄像机进行了相关的实验,对仿真结果进行验证,充分证明模型的有效性,揭示了空气电弧在外部磁场作用下,在低压断路器的灭弧室中的运动规律,并指出压力波在灭弧室中的传播和反射是产生这种运动规律的原因。此外,对阴极喷流所形成的双漩涡和电弧等离子体后部的“尾巴”这2种物理现象进行了详细的描述。

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.