Combustion of aluminum particles in flows of reactive gase

A model is proposed for the burning of individual aluminum particles in gas mixtures containing several oxidizing reagents, which included the buildup of oxide on an aluminum particle, the evaporation kinetics of Al, and surface chemical reactions. An analysis is made of calculations using this model with different gas flow parameters for particles with dimensions of 10–140 $\mu$m burning in air or in the gasification products of the solid fuel. A number of aspects of the combustion of aluminum particles are revealed which affect the burning time and the fraction of Al$_2$O$_3$ formed on a particle. the main feature associated with kinetic limitations and oxide buildup is a strong disequilibrium of the combustion process. The model provides a good description of the experimental dependence of the burning time of Al particles on their size and on the major flow parameters. The calculated fraction of Al$_2$O$_3$ which accumulates on a burning particle is in satisfactory agreement with experimental data.