CFD as an approach to understand flammable dust 20 L standard test: Effect of the ignition time on the fluid flow

Abstract

in Wiley Online Library (wileyonlinelibrary.com)A computational study based on the Euler-Lagrange approach was developed for the characterization of flammable dusts in the 20 L sphere standard test. The aim of the study was to analyze some parameters that might affect the experimental data (e.g., cold turbulence and particle size). The turbulence of a wheat starch cloud was described with the Detached Eddy Simulation model. Both the pressure of the system and the RMS velocity were compared with the flow patterns established with a particle image velocimetry analysis. It was concluded that the rebound nozzle forms a cloud that is composed by clumps. This fact implies dissimilarities between the local concentrations and the nominal value. Finally, a granulometric analysis established that the mean diameter of the particle size distribution (PSD) decreased by 69% during the dispersion. Thus, it is suggested to consider the PSD at the ignition zone rather than the PSD of the sample. V C 2017 American Institute of Chemical Engineers AIChE J, 64: 42-54, 2018

Nanopowders explosion: Influence of the dispersion characteristics

“…Moreover, the particle characteristics are more rapidly stable with a symmetrical nozzle and this stability is improved by using dust lifting instead of injection through a reservoir. It should also be underlined that no re-agglomeration phenomenon is visible during the dispersion, neither for aluminum nor for carbon black, which is not the case with powders such as starch (Vizcaya et al, 2018). Figure 4 shows the impact of the injection procedure on the particle size distribution of Corax N550.…”

“…The PIV set-up which was used to determine the turbulence level of the dust clouds in the 20L sphere is described by Vizcaya et al (2018). The dispersion of dust particles may generate changes in the turbulence of the fluid depending on the diameter of the dust.…”

Dust cloud explosion characteristics and mechanisms in MgH2‐based hydrogen storage materials

“…Studies have investigated the explosion characteristics of dust alone or dust mixed with flammable gas 8–13 . The addition of hydrogen to fuels (i.e., the hydrogen‐enrichment) strongly induces non‐linear (i.e., synergistic) effects in terms of burning velocity, 14 interaction of the propagating flame with the turbulent flow field 15–16 ; thus, explosion behavior 17–18 .…”

Inhibitory effects of three chemical dust suppressants on nitrocellulose dust cloud explosion

“…It has been shown that particle‐size distribution, agglomerate strength, and concentration of dust particles affect their dispersion process within a confined environment, thus impacting on the likelihood and severity of explosion . Vizcaya et al reported that the mean diameter of particles decreased by 69% during dispersion . Yu et al discovered that the agglomeration of particles is related to the behavior of flame propagation in dust explosion .…”

“…[20][21][22][23][24] Vizcaya et al reported that the mean diameter of particles decreased by 69% during dispersion. 25 Yu et al discovered that the agglomeration of particles is related to the behavior of flame propagation in dust explosion. 26 Peter et al reported that smaller particles exhibited higher maximum rates of pressure rise [(dP/dt) max ] until a threshold diameter (below which either the explosivity plateaus [organic dust typically]).…”