Explosion hazards of mixed aluminum/aluminum hydride dust cloud in a closed vessel

Aluminum (Al) and aluminum hydride (AlH₃) powders are important energetic materials but show an explosion risk when suspended in air. The explosion hazard of mixed dust forms the basis of safety design in industrial processes. In this work, the explosion characteristics and mechanism of Al/air, AlH₃/air, and Al/AlH₃/air were investigated by experiments and simulations. The results show that the induction time of Al dust explosion is longer than that of AlH₃, but the explosion severity of Al dust is smaller than that of AlH₃. For the three-component Al/AlH₃/air system, the addition of AlH₃ dust can shorten the explosion induction time of the mixed system. The maximum explosion pressure (P_max) of the dust mixture first increases and then decreases with mixed concentrations. At a mixed concentration of 900 g/m³ and an AlH₃ content of 80%, the P_max of the mixed dust is reached.