MODELLING OF ALUMINISED SOLIDPROPELLANT FIRE INDUCED BY THEPNEUMATIC EXPLOSION OF A LARGEROCKET MOTOR

摘要

In this work numerical modelling is performed to simulate the thermal effects of thepneumatic explosion of a large Solid propellant Rocket Motor (SRM). Such a blastinvolves fragmentation and dispersion of burning solid propellant pieces all around thebroken up SRM. Heat release rate from the propellant fire could then induce anotherSRM explosion and lead to a catastrophic scenario. For this reason heat transfer fromthe burning Al-based solid propellant pieces to the surroundings is especiallyinvestigated in this study. A Computational Fluid Dynamics (CFD) code that calculatesthe turbulent gas flow by a 3D fully coupled low Mach number model based on theLarge Eddy Simulation (LES) is adapted to simulate aluminised solid propellant fires atatmospheric pressure. Therefore it takes into account Al-droplet combustion through amixture fraction model for computing the heat release rate due to droplet oxidation. Theradiative absorption and diffusion of Al/Al2O3 droplets which are dispersed around thepropellant are also included. A comparison with preliminary experimental test datagives very promising results, and the methodology to predict the thermal environmentinduced by a SRM explosion in a motor assembling building is presented.