Evolution of Turbulent Burning Velocity and Turbulence Intensity during Aluminum Flame Propagation

Burning velocity, i.e. the consumption rate of the reactant by the flame front, is a key parameter for modelling flame propagation during accidental gas or dust explosions. Experimental investigations are thus needed to determine this burning velocity and to accurately validate numerical models. In this article, aluminum dust flame propagation inside a vertical tube is investigated. An innovative “direct method” is implemented to determine the burning velocity just ahead of the propagating flame front. This method is based on the Time-Resolved Particle Image Velocimetry (TR-PIV) technique to determine the unburned flow velocity. With this experimental setup, the turbulence intensity just ahead of the propagating flame front can thus also be estimated. Two granulometric distributions (with a median diameter of 6 μm and 20 μm), with three different dust concentrations for each granulometric distribution are investigated. An increase of the burning velocity with a decrease of the particle size is observed. Nevertheless, due to low levels of turbulence in front of the flame front during flame propagation, no significant influence of turbulence on burning velocity is observed during these experiments.