Article Dans Une Revue Combustion and Flame Année : 2026

Direct Numerical Simulation of single aluminum particle combustion in varying flow conditions

Simulation numérique directe de la combustion d'une particule d'aluminium isolée sous divers environnements

Résumé

This study presents a comprehensive numerical investigation of single aluminum particle combustion under varying convective oxidizing flow conditions, using Direct Numerical Simulations. A three-dimensional, boundary-layer-resolved model is developed to capture the complex interplay of gas-phase chemistry, surface reactions, and multiphase transport phenomena. The model incorporates aluminum evaporation, aluminum suboxide reactions at the particle's surface, and alumina formation both on the surface and in the gas phase. It also introduces an original scheme to account for the dissolution of alumina into the molten particle, based on parameters derived from molecular dynamics simulations. The model was validated against experimental burn time data. The unsteady combustion of a 125 μm-aluminum particle in various flowing O2/N2 conditions is then investigated in terms of standoff flame distance, gas-phase temperature and chemistry, particle temperature and surface chemistry. The results demonstrate that gas-phase reactions remain the dominant source of heat release, although surface reactions, particularly under highly oxygenated environments, play a significant role in modulating local combustion kinetics. The formation of liquid alumina at the particle's surface, its partial dissolution into the molten aluminum, and the limited surface coverage even at high O2 concentrations highlight the importance of coupling surface chemistry with thermal transport. While this mathematical model successfully reproduces the main macroscopic characteristics such as flame temperature, burn time-radius relationship, gas-phase composition, and fluxes, some discrepancies appear near the particle surface, i.e. at the microscale. These deviations can be attributed to radiative heat transfer effects which are not considered or to an incomplete understanding of surface reactions.

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Dates et versions

hal-05368240 , version 1 (17-11-2025)

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Lea Pillemont, O Simonin, Benoît Bédat, Guodong Gai, Pierric Caubet, et al.. Direct Numerical Simulation of single aluminum particle combustion in varying flow conditions. Combustion and Flame, 2026, 283, pp.114605. ⟨10.1016/j.combustflame.2025.114605⟩. ⟨hal-05368240⟩
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