Equation of state driven radiative models for simulation of lightning strikes
Abstract
This work is concerned with the numerical simulation of plasma arc interaction with aerospace substrates under conditions akin to lightning strike and in particular with the accurate calculation of radiative heat losses. These are important because they have a direct effect on the calculation of thermal and pressure loads on the substrates, which can lead to material damage under certain conditions. Direct numerical solution of the radiation transport equation (RTE) in mesoscale simulations is not viable due to its computational cost, so for practical applications reduced models are usually employed. To this end, four approximations for solving the RTE are considered in this work, ranging from a simple local thermodynamical behaviour consideration, to a more complex spectral absorption dependent on the arc geometry. Their performance is initially tested on a onedimensional cylindrical arc, before implementing them in a multidimensional magnetohydrodynamics code. Results indicate that inclusion of spectral absorption is necessary in order to obtain consistent results. However, the approaches accounting for the arc geometry require repeated solution of the computationally intensive Helmholtz equations, making them prohibitive for multidimensional simulations. As an alternative, a method using the net emission coefficient is employed, which provides a balance between computational efficiency and accuracy, as shown by comparisons against experimental measurements for a plasma arc attaching to an aluminium substrate.
 Publication:

arXiv eprints
 Pub Date:
 July 2021
 DOI:
 10.48550/arXiv.2107.04415
 arXiv:
 arXiv:2107.04415
 Bibcode:
 2021arXiv210704415A
 Keywords:

 Physics  Computational Physics;
 Physics  Plasma Physics
 EPrint:
 16 pages, 8 figures