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Analysis of the effects of altitude on arc column behavior by CFD modelling

Like any other electric arcs, lighting channels become unstable if the provided power is insufficient. One of the mechanisms assumed to be involved in the ignition of the recoil streamers phase is associated with the development of instability in the lighting channel. In order to study this phenomenon, ONERA in collaboration with EDF has performed 3D simulations of a part of the lighting channel in order to compute the main characteristic of the arc and understand in the future the physical conditions for the ignition of instability. In a first step, the computations of DC arc column have been performed and compared to the experiment of Tanaka et al. In a second step, the computations have been performed as a function of the pressure (1, 0.8 and 0.6 atm) in order to study the effects of the altitude (0, 2000 and 4000 meters).