Influential factors on the explosibility of unpremixed hydrogen/magnesium dust

The explosibility of unpremixed hydrogen/magnesium dust in a confined space was simulated and studied using a cubic explosion chamber. Typical influential factors, including hydrogen content in air, depth of magnesium layer, particle size distribution, ambient humidity, initial gas pressure and ignition position, on the explosion pressures of unpremixed hydrogen/magnesium dust in the first and secondary explosions were investigated. Experimental results showed that the biggest peak pressure values in the first and secondary explosions of the unpremixed hydrogen/magnesium dust were both obtained when the hydrogen content was 50%, and nitrogen participated the combustion of magnesium dust in the dust explosion. The effects of magnesium layer depth on the change trend of peak pressure in the first explosion was different from that in the secondary explosion for the unpremixed hydrogen/magnesium dust with a lean hydrogen concentration, and mean particle size of magnesium dust had a significant effect on the explosion pressure. Peak pressures in the first and secondary explosions both presented a trend of increasing at the early stage and then decreased with the increasing humidity or gas pressure, and the combustion mode of the unpremixed hydrogen/magnesium dust varied as the ignition position was changed. (C) 2020 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved.