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Article Dans Une Revue Combustion and Flame Année : 2021

Modeling the self-propagation reaction in heterogeneous and dense media: Application to Al/CuO thermite

Résumé

This article provides a computational analysis of the reaction of fully-dense layered aluminum and copper oxide systems. After the detailed presentation of the 2D nonstationary model implementing both oxygen and aluminum diffusion, the propagation of the reaction front in an Al/CuO thin film was studied. The model qualitatively reproduces the dependency of the reaction front progression rate spatially as a function of the fuel concentration. Calculations also evidence the inverse evolution of flame front width with respect to the reaction front velocity. A procedure to estimate the heat loss generated by the fact that the reactants and products may vaporize prior to reaction completion was proposed by imposing a flame temperature limit close to Cu vaporization point. This work also shows that microscopic fluctuations in the instantaneous reaction front velocity can be observed for reactant diffusion activation energy (Ea) of 125 kJ/mol, before quenching for greater Ea. Finally, we demonstrate the potential of this new 2D nonstationary model to investigate the thermal effect of additives such as metallic impurities in the Al/CuO thin film that can lead to the flame front corrugation at the microscale. The simulations show that a metallic particle acts first to boost the reaction velocity as its high thermal conductivity helps the upfront heating. Then, the particle being also a heat sink, a local slowing down of the front velocity is observed.
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Dates et versions

hal-03139669 , version 1 (12-02-2021)

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Emelian Tichtchenko, Alain Estève, Carole Rossi. Modeling the self-propagation reaction in heterogeneous and dense media: Application to Al/CuO thermite. Combustion and Flame, 2021, 228, pp.173-183. ⟨10.1016/j.combustflame.2021.01.040⟩. ⟨hal-03139669⟩
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