Explosion suppression flame and mechanism of energetic dust with distinct morphologies: Aluminum-containing metal as a typical

Abstract

A series of explosion suppression experiments on aluminum powder with diverse morphologies were carried out in vertical pipelines. By combining the flame propagation images and flame temperatures, the physical and chemical effects of inhibitors on the flame propagation of spherical aluminum powder (S Al ) and flaky aluminum powder (F Al ) were explored. The results demonstrated that the amount of inhibitor required for F Al was greater than S Al , and the chemical effects of piperazine pyrophosphate (PPAP) were more effective in inhibiting S Al , whereas the physical effects of nano-SiO 2 were more significant in suppressing F Al . PPAP dramatically reduced the flame propagation velocity, flame temperature, and flame propagation maximum height of S Al as the inhibitor mass fraction increased. The flame temperature, ignition delay time, and flame illumination of F Al could even be considerably changed by nano-SiO 2 . The microscopic and macroscopic suppression mechanisms of PPAP and nano-SiO 2 on different morphology of aluminum powder were proposed. • PPAP displays superior performance in inhibiting spherical aluminum powder. • Flake aluminum powder explosion suppression is more difficult than spherical powder. • Nano-SiO 2 can significantly affects the explosion of flake aluminum powder. • Microscopic and macroscopic suppression mechanisms of PPAP and nano-SiO 2 are studied.