Explosion simulations in industrial risk studies using 3D CFD coupled with structural analysis

Abstract
Recent events have emphasized explosion simulations in industrial risk studies. Two main information are looked for : the pressure time history signal of an air blast ; and the structural analysis to determine the damages undergone by the structural integrity. Most of the software available for explosion studies deal only with the first issue. Moreover a lot of cells are usually needed in the detonation wave to constitute the front after combustion. The usual method consists in developping an ID spherical wave. Once the wave is formed, it is remapped on the 3D mesh of the real domain. We present here a 3D methodology capable of modeling the combustion of the explosive with only a few cells while getting the theoretical Chapman Jouguet parameters of pressure, density and detonation velocity. The approach was validated against some experimental cases used in the defense domain. Then, this methodology has been applied to an actual industrial risk study. fluidyn-FSI has been chosen for the implementation of this method because of its capabilities in fluid-structure interactions. This software allows for a strong coupling between finite volume analysis for fluids and finite elements methodology for structures, which is extremely useful for subsequent structural integrity calculations.