Flame behaviours and deflagration severities of aluminium powder–air mixture in a 20-L sphere: Computational fluid dynamics modelling and experimental validation

Abstract

Flame behaviours and explosion severities are vital for conducting risk evaluations, obtaining a dynamic control, and determining propagation mechanisms of aluminium dust explosions. In this study, a three-dimensional (3D) mathematical framework and a computational fluid dynamics (CFD) model were established to numerically reveal the dynamic evolution of flame morphology, deflagration severities, and heterogeneous combustion properties of an explosion due to an aluminium dust–air mixture by using a standard 20-L spherical chamber. Moreover, the validity of the numerical model was precisely verified using an experiment. Furthermore, the flame propagation and explosion process of the aluminium dust–air mixture were reproduced using the 3D CFD model. The dynamic behaviour of flame in the initial explosion stage and explosion parameters pertaining to three dust concentrations were qualitatively and quantitatively investigated using numerical calculation and experimental comparison. Results revealed that the flame morphology and explosion pressure obtained by conducting numerical simulation demonstrates a favourable agreement with those obtained using experimental observation. This indicates that the 3D CFD model presented in this study is appropriate for conducting numerical predictions on other dust explosions. Finally, the flame propagation mechanism and feedback of the aluminium dust–air mixture explosion were proposed on the basis of the obtained experimental and numerical information. This preliminary study can be conducive to hazard assessment and disaster-causing mechanism determination of dust-based explosions.