Study on explosion characteristic parameters and induction mechanism of magnesium powder/hydrogen hybrids

Abstract

• 1. The explosion pressure curve of the hybrids appear double-peaked structure. • 2. Hybrids have greater explosion severity and temperature than single combustible. • 3. Mg particle is more prone to homogeneous shrinking core reaction in hybrid explosion. • 4. After the explosion of any hybrid system, there will be H 2 remaining. • 5. Oxygen content of hybrid explosion products is lower than that of magnesium powder. The explosion of magnesium powder/hydrogen hybrid is a complex reaction process, which will cause more serious harm than the explosion of a single combustible medium. The research on the mechanism of the hybrid explosion can provide corresponding reference for the prevention of such accidents. A 20L explosion device was used to study its explosion mechanism, and the results show that the magnesium particles in the hybrid explosion underwent homogeneous shrinking core reaction. It is found that the explosion pressure curve of the hybrid will appear bimodal structure under certain conditions, so this paper will explore it separately. When the hybrid system is in the “oxygen-poor” state, the explosion characteristic parameters of the first stage will decrease with the increase of combustible materials. And the hydrogen content and oxygen consumption in the gaseous products are also increase gradually, and unreacted magnesium particles are also found. In the “oxygen-rich” state, the opposite is true, and the number of cubic particles and the oxidation degree in the solid explosion products increasing with the increasing combustible materials. In addition, even under “oxygen-rich” conditions, hydrogen remains in the gaseous product of the hybrid. Interestingly, even under the condition of 30%vol-50%vol hydrogen/magnesium powder hybrid in the “oxygen-poor” state. As the combustible materials increase, the explosion characteristic parameters and maximum explosion temperature in the second stage show a change trend of increase first and then decrease.