A two-dimensional numerical model of the interaction between an electric arc and a solid anode of different types is presented in this study. The CFD commercial code FLUENT is used to model the plasma flow and the solid anode domain. Quantities such as the velocities or the temperature are presented, and the energy transfer components between the plasma and the anode are quantified. Comparisons of the calculated results with the available experimental data in the literature show that the model predictions are in good agreement. In the case of argon gas and a copper anode, with the distance between the two electrodes 10 mm, the maximum temperature near the cathode tip is 21 000 K for a current of I = 200 A. For the same configuration, the maximum of the current density in the copper electrode is found to be −2.5 × 106 A m−2. The electrical flux is the main component of the transferred flux on the anode. Once validated, our model is applied to other theoretical and experimental configurations and allows us to study several parameters when attention is focused on the influence of metal vapour from the vaporization of the anode or the current-carrying path in the electrode on the arc behaviour. According to the current-carrying path in the anode, the current density distribution is affected in the material and its surface.

This paper reports the second part of the study of an electric arc and its interaction with the anode material. First, a three-dimensional model is presented and validated in a natural symmetric configuration for which many experimental results exist. In the three-dimensional model, two situations are considered for the anode surface: the classical zero heat flux condition and the use of the anode model. In the second case, the specific properties of the anode material are taken into account and play a role in the current conservation between the plasma and the anode, and therefore, affect the arc behaviour near the electrode. The results for the two approaches are similar in two dimensions, but differences exist in real three-dimensional cases when external forces such as cross flow or magnetic field tend to bend the arc. Second, we present a comparison between the two methods in the case where the arc is deviated by an external magnetic field. For this comparison, we adopt a configuration used at Odeillo during the 1970s and compare the results obtained by our code with the experimental ones. We find that it is essential to consider the complete anode model if the arc deflection is to be predicted correctly. Once our developments are validated, the computational code is applied in a free-burning arc configuration, where the plasma column is deflected by an external cross flow.

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A numerical model is proposed to describe the arc and its interaction with a composite material in an anodic configuration. After a validation step with experimental results in two dimensions (2D) from the literature, the model is used to quantify the degradation level of the material versus the pulse duration and the current intensity value. The flux components show the importance of the Joule effect in the composite. Then, in order to simulate the aircraft displacement, an external convective force is applied. A three-dimensional (3D) model is thus developed and used to evaluate the degradation of the composite material. This model shows the behaviour of the plasma column representing the lightning strike and quantifies the power transferred to the anode.

In this paper, we present the study realized on three experimental setups that produce in laboratory a free arc channel subjected to the transient phase of a lightning current waveform. This work extends the high current pulsed arc characterization performed on previous studies for peak levels up to 100 kA. Eleven high current waveforms with peak value ranging from 100 kA to 250 kA with different growth rates and action integrals are studied, allowing the comparison of different test benches. These waveforms correspond to standard lightning ones used in aircraft certification processes. Hydrodynamic properties such as arc channel evolution and shock wave propagation are determined by high speed video imaging and Background-Oriented Schlieren method. The arc diameter reaches around 90 mm at 50 µs for a current of 250 kA peak. Space-and time-resolved measurements of temperature, electron density and pressure are assessed by optical emission spectroscopy associated with the radiative transfer equation. It is solved across the arc column and takes into account the assumption of non-optically thin plasma at local thermodynamic equilibrium. For a 250 kA waveform, temperatures up to 43000 K are found, with pressures in the order of 50 bar. The influence of current waveform parameters on the arc properties are analysed and discussed.