Combustion and Flame, Vol.206, 112-122, 2019
A numerical study on heterogeneous aluminum dust combustion including particle surface and gas-phase reaction
A numerical simulation on aluminum (Al) dust combustion is conducted using the reactive Eulerian-Lagrangian method. A suggested combustion model of a single aluminum (Al) particle is applied to the Lagrangian solver. The combustion model includes heat transfer in the transition regime (i.e., between a continuum and free-molecular regime), radiation, melting, surface reaction, aluminum vaporization in fuel rich and lean conditions as well as gas phase kinetics. The finite volume method based in-house code solves the particle dynamics and gas flow induced by the particle combustion to simulate flame propagation in a half-open tube. Numerical results are compared with experimental measurements. Both sets of results reveal a tendency toward the Al dust flame, which has a constant burning velocity in fuel-rich conditions and decreasing burning velocity in lean conditions. The numerical simulation analysis indicates that the constant burning velocity is due to the trade-off between the particle reaction surface and maximum flame temperature. Additionally, flame structures at different aluminum concentrations and heterogeneous characteristics are evaluated. The parametric study then examines the effects of thermophoretic force and particle diameter on the burning velocity. (C) 2019 Published by Elsevier Inc. on behalf of The Combustion Institute.