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Electrical arcs in circuit breakers are very complex phenomena involving many aspects of Physics: fluid mechanics, radiative processes, electromagnetics ... and their numerical modelling exhibits various couplings. After a physical analysis of the phenomena, showing which couplings are important and which are not, we present axisymmetric simulations of arcs for two kinds of SF6 breakers, a two pressure breaker and a rotary arc breaker. We focus our study on the coupling between fluid mechanics and electromagnetics (influence of Laplace forces on the flow, stability).

We present in this paper a magnetohydrodynamic (MHD) modelling of the gliding arc behaviour of a dc plasma torch operating with air under low current and high voltage conditions. The low current leads to instabilities and difficulties with simulating the process because the magnetic field is not sufficient to constrict the arc. The model is 3D, time dependent and the MHD equations are solved using CFD software Code Saturne®. Although the arc is definitively non-local thermodynamic equilibrium (LTE), the LTE assumption is considered as a first approach. The injection of air is tangential. A hot gas channel reattachment model has been used to simulate the restriking process of the arc root. After the description of the model, the most appropriate electrical voltage breakdown parameter has been selected in comparing with experimental results. A typical operating point is then studied in detail and shows the helical shape of the arc discharge in the nozzle. Finally, the mass flow rate and the current have been varied in the range 0.16-0.5 g s-1 and 100-300 mA, respectively, corresponding to typical glidarc operating points of our experimental plasma torch. The model shows good consistency with experimental data in terms of global behaviour, arc length, mean voltage and glidarc frequency [ABSTRACT FROM AUTHOR]

This paper describes the initial results of a 3D flow simulation of a molten glass bath and a transferred electric plasma arc between two aerial metallic electrodes. The calculations were performed as part of a joint CEA-EDF study. The ESTET 3.4 CFD calculation code used to simulate electric arc furnaces in the metallurgical industry was applied here to model glass melting by an oxygen transferred arc plasma in order to optimise the treatment of radioactive waste. This method could be applied to industrial or municipal waste. The high temperature obtained by the plasma allows us to burn the organic fraction of the waste and then, the mineral part of this waste is trapped in the glass melt. [ABSTRACT FROM AUTHOR]