Characterization of high-current pulsed arcs ranging from 100--250 kA peak

In this paper, we present the laboratory study on three experimental setups that produce a free arc channel subjected to the transient phase of a lightning current waveform. This work extends the high-current pulsed arc characterization performed in previous studies for peak levels up to 100 kA. Eleven high-current waveforms with peak value ranging from 100--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 the background-oriented Schlieren method. The arc diameter reaches around 90mm at 50 $\mu$s 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 43000K are found, with pressures in the order of 50 bar. The influence of current waveform parameters on the arc properties are analyzed and discussed

Simulation of the Lightning Arc Root Interaction with Anisotropic Materials

International audienceThe interaction between lightning arcs and composite materials is a challenging issue for maintenance and safety considerations in the aerospace industry [1]. Composite materials exhibit a much lower conductivity than metallic materials, as well as an important anisotropy due to the orientation of the fibres and the insulating nature of the matrix. In this study, the impact of the anisotropy of composite materials on the lightning arc root dynamics during the pulsed arc phase has been focused. A finite-volume compressible MHD code including Joule heating, Laplace forces and radiative fluxes has been used in a simplified 2D configuration with a single layer composite material. The different current distributions in the arc root are examined up to 30 µs for different ratios between longitudinal and perpendicular conductivities

Experimental characterization fo the interaction between a high current arc and aeronautical materials

International audienceIn this paper, we present the work realized on an experimental setup which simulates in laboratory the transient phase of a lightning arc applied to aluminum samples with different thicknesses and surface coatings. A high current pulsed arc is utilized in this study, which has a peak value of 100 kA and a peak time to around 12 μs. This device is instrumented with high speed video cameras to assess the geometric characteristics of the arc attachment on the material.The shock wave generated by the arc expansion is analyzed near to the surface material, using theBackground-Oriented Schlieren method. The position and velocity of the wave front and the arc root radius are determined up to 70 μs, when the lightning arc is applied to aluminum samples with different paint thickness. Finally, we perform comparisons with previous results of the hydrodynamic properties of a free arc channel subjected to the same level of current, but without the material’s interaction