On Aluminum Flame Propagation in a Smooth Vertical Tube: Experimental Study and Analogies with Premixed Gaseous Flames

Aluminum dust flame propagation inside a smooth vertical tube from its closed end is studied through a joint analysis of experimental measurements and numerical simulations. In addition to the common information about flame shape and position over time, flow velocity and turbulence intensity ahead of the propagating flame front are accessed using time-resolved particle image velocimetry. Both experimental measurements and numerical simulations based on a turbulent flame-speed modeling approach are used to identify the most important features of propagation mechanisms. While the turbulent flame-speed model does not intend to be predictive owing to rather rough simplifying assumptions, the simulation results show that the G-equation modeling approach correctly predicts the flame propagation. Both experiments and numerical simulations support a mechanism where turbulence plays only a supplementary role in the flame propagation mechanism. Finally, on the basis of a geometrical model, it is highlighted that aluminum dust flame propagation in a half-open smooth tube exhibits similar behavior in comparison with gaseous flames.