Effects of different particle size distributions on aluminum particle–air detonation

Abstract

Due to the involvement of powder materials in dust explosion hazards and detonation experiments, it is imperative to analyze the heterogeneous detonation in a polydisperse suspension with a continuous particle size distribution. Notably, most current studies are limited to monodisperse suspensions with only one particle size. In this study, the rich 2 μm aluminum particle–air detonation with two particle size distributions (namely, the monodisperse and the polydisperse with log-normal particle size distribution) is numerically studied by using the Eulerian–Lagrangian method along with a new hybrid aluminum combustion model. Significant discrepancies of the one-dimensional detonation front structures are observed between the monodisperse detonation and the polydisperse counterpart. And, the physical mechanisms of these discrepancies have been revealed by decoupling the gas–particles interactions with the one-dimensional flow theory. It is mainly caused by the different timings of the particle phase transition processes and the consequently different heat transfer characteristics, which are the effects of multiple timescales and length scales in the polydisperse detonation. Furthermore, owing to the wider reaction zones of polydisperse detonations than that of the monodisperse counterpart, discrepancies of two-dimensional detonation cell sizes are observed as well. This study reveals the great importance of considering particle size distribution in heterogeneous detonation simulations.