Simulation of the gasdynamic and electromagnetic processes in low voltage switching arcs

The switching arc in a low voltage circuit breaker is a very complex phenomenon, which is determined by the interaction between heat conduction, gas flow, current flow, and magnetic forces. A realistic simulation of the switching arc must consider all these effects. In this paper, a three-dimensional (3-D) simulation model is described, which is based on the differential equations for the mass, momentum, and heat balance. Furthermore, it contains a potential differential equation for the calculation of the current flow and the resulting magnetic field. This set of equations is solved by the finite volume method. First results are presented, which show the shape of the arc and the gas flow while the arc is moving between rail electrodes in a simple arc chamber