Numerical modelling of electrode plasma generation

Summary form only given. Arc erosion due to material transfer in the plasma developed between low voltage switching devices during opening and closure is one of the major mechanisms leading to contact failure. Electrical contact failure can have relatively catastrophic consequences. This work is primarily concerned with the arc phenomena associated with low voltage switching devices during the breaking of two current carrying electrical contacts. It is assumed that the electrode plasma is initiated by the application of electric potential between electrodes which gives rise to a strong electric field which draws electrons from the cathode. This then generates a non-linear responses in the gas, involving fluid and reactive effects. A numerical solution to the Navier-Stokes equations in a multi-species, nonequilibrium reacting, viscous nitrogen plasma flow under the electrical arcing condition is presented here. Here, a convection-diffusion-ionization operator splitting scheme is adopted. The Navier-Stokes equations are divided into separate partial differential equations that describe respectively the convective, diffusive, chemical and electromagnetic effects separately. A further geometric operator splitting is applied, in which the various part of the equations are reduced to a sequence of one-dimensional problems along grid lines which are relatively easy to solve conceptually. This has the advantage of maintaining sharp resolution of discontinuities and monotonicity in the solutions.