Wu Mingliang

This paper focuses on the numerical investigation of arc plasma behaviour in air direct current circuit breaker (DCCB) considering the effect of turbulence with K-epsilon model. A three-dimensional simulation model of a certain type air DCCB is built and calculated, which is based on magneto-hydrodynamic (MHD) theory. Electromagnetic and gas dynamic interaction is considered through solving the Navier-Stokes equations coupled with Maxwell equations, which are connected by source terms (Joule heat and Lorentz force calculated in electromagnetic field) in the conservation equations. A thin layer of nonlinear electrical resistance model is used to represent the anode and cathode falls of arc runner produced by plasma sheath [1-2]. In the simulation results, the arc plasma shape and motion are described in detail by the temperature distributions. Some important phenomena are observed in the simulation, such as the different arc shapes, moving speeds and so on when the turbulence is considered. Finally, with the arc voltage obtained experimentally, the simulation with turbulence considered shows much agreement with the experiment result.