Combustion model for thermite materials integrating explicit and coupled treatment of condensed and gas phase kinetics

Nanothermites are interesting energetic systems as their combustion driven by the oxidation of metallic fuel associated with reduction oxidizer, can produce extremely fast burning rates exceeding hundreds m s−1. In addition, changing reactant (composition, stoichiometry) geometry and compaction conditions, control rate be achieved, allowing designer to customize chemical energy for each application. To date, only rough models exist, most restricting mechanisms condensed phase processes, thus providing an approximative prediction structure-combustion performance relationships. This work presents a tri-phasic model Al/CuO powder considering 9 gaseous species (Al, Cu, O2, O, Al2O, Al2O2, AlO, AlO2, N2) 4 CuO, Al2O3) that liquid or solid. The reactionnal scheme involves 12 heterogeneous reactions 2 changes based on diffusional kinetics, while considered through equilibrium. A detailed description theoretical formulation numerical method is presented, followed discussion closed-bomb simulation. highlights great impact Al particles initial diameter pressure development in chamber. After initiation stage, decomposition CuO releases which spontaneously absorbed surface submicronic diffuses alumina react pure Al. At high temperature, copper, aluminum sub-oxides condense both particle types. By contrast, micron-size limits quantity O2 absorption condensation, leading formation pre-peak times higher than final chamber pressure.