Explosion severity behavior of micro/nano-sized aluminum dust in the 20L sphere: Influence of the particle size distribution (PSD) and nozzle geometry

Due to its industrial applications, the assessment of the explosibility parameters of aluminum powder is essential. However, they strongly depend on the Particle Size Distribution (PSD), which impacts both the rate-limiting step of the combustion mechanism and the radiative transfer. This article describes the influence of the test procedure on the explosion severity of six aluminum samples, having primary particle diameters ranging between 0.04 and 125 mu m. The PSD measured in situ after dispersion in a 20 L sphere differs from those obtained before dispersion, particularly for nanoparticles for which the presence of agglomerates is evidenced. The explosion severity parameters were measured at different turbulence levels by changing the nozzle geometry and ignition delay time. The impact of the injection procedure varies from micron-sized aluminum dust to nanoparticles due to their low inertia. Moreover, if an alternative nozzle could be more appropriate at a lower turbulence level, the rebound nozzle is always the most conservative option for standard test conditions. Finally, the mean particle surface area was identified as an appropriate indicator of the micro/nano scale's explosivity performance. Results suggest that below 3 m2/g, the combustion would be diffusion-limited and kinetic-limited otherwise. (c) 2021 Institution of Chemical Engineers. Published by Elsevier B.V. All rights reserved.

Automated summary

This article examines the impact of test procedures on the explosion severity of six aluminum samples with primary particle diameters ranging from 0.04 to 125 µm. The study finds that the test procedure has different effects on micron-sized aluminum dust and nanoparticles, with the presence of agglomerates significantly affecting the test results.