Combustion of nano aluminum particles (Review)

Nano aluminum particles have received considerable attention in the combustion community; their physicochemical properties are quite favorable as compared with those of their micron-sized counterparts. The present work provides a comprehensive review of recent advances in the field of combustion of nano aluminum particles. The effect of the Knudsen number on heat and mass transfer properties of particles is first examined. Deficiencies of the currently available continuum models for combustion of nano aluminum particles are highlighted. Key physicochemical processes of particle combustion are identified and their respective time scales are compared to determine the combustion mechanisms for different particle sizes and pressures. Experimental data from several sources are gathered to elucidate the effect of the particle size on the flame temperature of aluminum particles. The flame structure and the combustion modes of aluminum particles are examined for wide ranges of pressures, particle sizes, and oxidizers. Key mechanisms that dictate the combustion behaviors are discussed. Measured burning times of nano aluminum particles are surveyed. The effects of the pressure, temperature, particle size, and type and concentration of the oxidizer on the burning time are discussed. A new correlation for the burning time of nano aluminum particles is established. Major outstanding issues to be addressed in the future work are identified.