Comparison of Combustion Characteristics of Magnesium and Aluminum Powders
Résumé
This work presents an experimental study of the combustion characteristics of micron-sized aluminum andmagnesium powders under constant volume combustion experiments. Burning velocities were estimated from the measured pressure traces using both a simplified model for combustion on closed spherical bombs and a semi-empirical correlation for dust explosions, and compared to previous literature. Flame temperatures were measured by bi-color pyrometry and indicate that, for aluminum powders with a mean particle diameter smaller than 12 μm, the flame moves closer to the particle’s surface. However, emission spectra obtained during combustion indicate that vapor-phase oxidation exists for all studied powders. Analysis of the combustion products further supported the presence of a vapor-phase reaction. For aluminum, the residue is composed by partially crystallized nanometric spheres as fine as 200 nm. MgO was found in crystallized cubic structures of different sizes, the finest ones also about 200 nm.