The Influence of Aluminum Particle Size, Ambient Pressure and Oxygen Concentration on the Ignition and Combustion Times of Particles in the Air Suspension
A. P. Shpara, D. A. Yagodnikov, A. V. Sukhov
Bauman Moscow State Technical University, Moscow, Russia
Keywords: aluminum, particle, aerosol, combustion, modeling, micro- and nanosizes
Abstract
An approach is proposed for determining the reaction characteristics of aluminum particles in an aerosol. This approach takes into account changes in heat and mass transfer mechanisms as the burning particle size decreases, from a continuous-medium regime (the mean free path of gas molecules is significantly greater than the particle diameter) to a free-molecular regime (ultra-small particles). Modeling the combustion of an aluminum particle, taking into account changes in heat and mass transfer regimes and a decrease in oxygen concentration in the air over a range of oxidizer excess ratios from 1.05 to 2.5 and pressures from 0.1 to 4 MPa, allowed us to identify the determining factor in the decrease in the average mass concentration of the oxidizer during particle combustion, leading to an increase in combustion time in the free-molecular regime relative to the combustion time calculated under a continuous-medium assumption.
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