Combustion of nano aluminum particles (Review)

Abstract

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.

Ignition and combustion of high-energy materials containing aluminum, boron and aluminum diboride

“…In studies aimed at studying ignition and combustion at high pressures [13] or under conditions close to real ones [1,13] the conductive initiation (for example, heating with nichrome filament or hot gases in TGA chamber) was used. It was established that with an increase in the pressure and content of boron particles to 20 mass.…”

“…Boron is one of the most promising metals for rocket fuels due to high specific combustion heat value (among the highest per unit of mass and the maximum possible per unit of volume [1]). However, its application is significantly complicated by the fact that inert layer of boron is formed on the surface of boron particles during storage and combustion.…”

Numerical Simulation of a Vortex Combustor Based on Aluminum and Steam

“…The ignition temperature [14,27] is obtained by fitting the experimental data under different particle sizes. The fitting formula is T ig = 1366.4 + 205.97673 ln(d + 0.24173).…”

“…According to the existing research, the combustion law of aluminum particles is basically based on the combustion experiments [11][12][13][14][15][16][17] of single particles and particle groups, and various particle size and burning time laws were obtained, such as d 1.8 and d 1.5 . At the same time, there are many studies from the perspective of the mathematical model theory [14,[18][19][20][21][22], whereby when the particle size of the aluminum particles is large, the combustion is controlled by the continuum regime, whereas, for the nano-aluminum particles, the combustion is controlled by the free-molecule regime, and when the particle size is between these two extremes, the combustion is controlled by a transition regime.…”

“…At the same time, there are many studies from the perspective of the mathematical model theory [14,[18][19][20][21][22], whereby when the particle size of the aluminum particles is large, the combustion is controlled by the continuum regime, whereas, for the nano-aluminum particles, the combustion is controlled by the free-molecule regime, and when the particle size is between these two extremes, the combustion is controlled by a transition regime. In the calculation of the current flow field of aluminum particles, basically the burning time change law (d n law) of aluminum particles obtained by experiments is adopted.…”