Explosion characteristics of AlH3 dust cloud with varying micron particle sizes

Abstract

The explosion characteristics of AlH3 dust clouds with varying micron particle sizes are investigated in this paper. The explosion mechanism of AlH3 dust clouds is initially explored. The results indicate that the activation energy for hydrogen evolution shows an increasing trend with the AlH3 particle size, and both of these values are comparable to the 30 kJ/mol desorption energy of hydrogen from large AlH3 clusters. Due to the rapid dehydrogenation rate and small-size residual aluminum core, fine AlH3 particles exhibit a continuous gas-phase flame and fast propagation velocity. With increasing particle size, the lower dehydrogenation rate, reduced specific surface area, and higher volume heat capacity contribute to a higher level of incomplete reaction. Consequently, large micro-sized AlH3 particles display a discrete flame, slower flame velocity, and lower explosion pressure. The flame delamination phenomenon is not observed in our experiments on AlH3 dust clouds.