Inhibition evaluation of gas inhibitors in micron-sized aluminum dust explosion

The inhibition effects of gas inhibitors (nitrogen, carbon dioxide, and heptafluoropropane) on aluminum dust explosion were investigated experimentally and numerically. The results showed that as the inhibition volume fraction increased, the flame propagation characteristics parameters and explosion severity parameters were inhibited by inert gases accordingly. The inhibition performance of carbon dioxide was superior to that of nitrogen, and the minimum inhibition volume fractions of nitrogen and carbon dioxide were determined. XRD results indicated that the crystal form of major condensed product of aluminum dust explosion using two kinds of inert gas as inhibitors was different due to the distinct inhibition effect. Moreover, the XPS analysis revealed that the nitrogen oxide of aluminum adsorbed on the surface of aluminum particles blocked gasification process of aluminum particles. To explore the inhibition mechanism microscopically, a kinetic model concerning gas phase combustion was established. The above discussion indicated that the inhibition effect was the combination of multiple factors. In addition, due to the strong reactions between aluminum particles and heptafluoropropane, it cannot be regarded as gas inhibitor in aluminum dust explosion.