CFD simulations of dust dispersion in the 1 m3 explosion vessel

According to standard procedures, flammability and explosion parameters for dusts and dust mixtures are evaluated in 20 L and/or 1 m(3) vessels, with equivalent results provided a correct ignition delay time (60 ms in the 20 L vessel; 600 ms in the 1 m(3) vessel). In this work, CFD simulations of flow field and dust concentration distribution in the 1 m(3) spherical vessel are performed, and the results compared to the data previously obtained for the 20 L. It has been found that in the 1 m(3) vessel, the spatial distribution of the turbulent kinetic energy is lower and much more uniform. Concerning the dust distribution, as in the case of the 20 L, dust is mainly concentrated at the outer zones of the vortices generated inside the vessel. Furthermore, an incomplete feeding is attained, with most of the dust trapped in the perforated annular nozzle. Starting from the maps of dust concentration and turbulent kinetic energy, the deflagration index K-St is calculated in both vessels. In the conditions of the present work, the K-St is found to be 2.4 times higher in the 20 L than in the 1 m(3) vessel.