Abstract: In order to select the particle size parameters which can characterize the explosion characteristics of aluminum powder and improve the accuracy of aluminum powder explosion risk assessment, the influence of particle size distribution on the explosion characteristic parameters of aluminum powder under the span of large particle size distribution was analyzed, and the explosion sensitivity of aluminum powder was studied. The influence of dispersity on the minimum explosive concentration (MEC) and minimum ignition energy (MIE) of micron-sized aluminum powder was investigated by using Siwek 20 L vessel apparatus and Hartmann tube. The results show that the explosion sensitivity parameter of aluminum powder accelerates with the increase in particle size. When the particle size of aluminum powder is small, the influence of particle size change on MEC and MIE is relatively small; for the mixed aluminum powder sample with larger particle size span, the small particle size dust component acts as a potential ignition source, which reduces the MEC and MIE measurements and greatly increases the aluminum powder explosion risk. It can be seen from Pearson correlation analysis that the particle size parameters D_3,2 (Saucter mean diameter) and D₄₀ (40th percentile of particle size) have the highest correlation with MEC and MIE. The correlation coefficients of D_3,2 with MEC and MIE are 0.962 7 and 0.746 0, and the correlation coefficients of D₄₀ with MEC and MIE are 0.947 9 and 0.741 1. In contrast, the size polydispersity (σ_D) and particle size span (PSS) have weak correlation with MEC and MIE. Therefore, it is more appropriate to choose D_3,2 and D₄₀ as the main expression of particle size distribution in the study of aluminum powder explosion sensitivity.

Key words: aluminumpowderexplosion, dispersity, minimumignitionenergy, minimumexplosiveconcentration, Pearsoncorrelationcoefficient