Measurement of Burning Time and Flame Speed of Aluminum Dust Flame in Constant Pressure

Thermodynamic calculations of the combustion heat release, specific impulse, and volumetric specific impulse show that metal fuels can exceed hydrocarbon fuels in volumetric energy content and in the case of boron exceeds conventional fuels on a mass basis as well. The refractory nature of metal fuels and their combustion products also suggest that they may permit ramjets utilizing subsonic combustion to extend their operation to hypersonic Mach numbers. In this paper, formation of stabilized flame using a pure powderedmetal fuel without the use of hydrocarbons is investigated experimentally. The ability to effectively inject powdered metal into a combustor is demonstrated using a laboratory-scale dispersion apparatus. Dynamic parameters of burning time and flame speed of aluminum dust flame have been measured by dust combustion apparatus. Results imply that the burning time is decreased, while the oxygen concentration is increased. Also, the replacement of nitrogen with argon increases burning time. This is so, because of the increase in aluminum dust reaction rate. The flame speed of aluminum dust is near the diffusion flame and its differences with hydrocarbon fuel flame is to stablize the dust flame in rich mixtures.