Dust explosions: CFD modeling as a tool to characterize the relevant parameters of the dust dispersion

These approaches have evidenced three different stages of solids dispersions, which can be classified according to variations in particle size distributions: a fragmentation phase, stabilization of the dust cloud and sedimentation phase. These facts suggest that, for the micrometric aluminum powders which have been tested, the minimum ignition delay must be 60 ms, after considering the distribution of the discrete phase inside the tube and the variations in size distribution at the elevation of ignition electrodes. This delay being greatly influenced by powders properties, this paper suggests combining both simulation and experimental approaches in order to determine the most relevant or the most conservative conditions for the determination of dust flammability.