Proportional effects of RDX/Al mixtures on dust explosion characteristics, flame behavior, and explosion mechanism

RDX/Al mixtures are widely utilized in energetic materials, yet their hybrid dust generated during production and application poses potential explosion hazards. Moreover, the synergistic explosion mechanisms remain poorly understood, particularly at varying dust concentrations. This study systematically investigates the effects of different aluminum powder mass percentages and dust concentrations (300 g/m3, 600 g/m3, 900 g/m3) on RDX dust explosion severity, flame propagation behavior, and gaseous products. The results indicate that the maximum explosion pressure peaks at 35% RDX, 65% RDX, and 80% RDX at 300 g/m3, 600 g/m3, and 900 g/m3, respectively. Concurrently, the time for the flame to propagate to the wall (t1) reaches minimum values of 34.8 ms, 25.66 ms, and 23.93 ms. The maximum rate of pressure rise is observed for pure RDX at 900 g/m3. Aluminum powder enhances flame propagation velocity and combustion duration, as validated by the flame propagation system. Overall, the concentrations of carbon oxides (CO+CO2) decrease significantly with increasing aluminum mass percentage. At 20% RDX, the concentrations decreased by 51.64%, 72.31%, and 79.55% compared to pure RDX at 300 g/m3, 600 g/m3, and 900 g/m3, respectively. Notably, N2O concentration only at 300 g/m3 showed such a trend. It rises first and then falls at 35% RDX at 600 g/m3 and 900 g/m3. These findings elucidate the synergistic explosion mechanisms and provide critical guidelines for safe production and handling.