Experimental and Mechanistic Study on the Flame Propagation Behaviors of Corn Starch Deflagration Inhibited by Different Powder Inhibitors

ABSTRACT This paper investigates the inhibitory effects and mechanisms of different powder inhibitors on corn starch explosion flame propagation. The results indicate that ABC powder exhibits the strongest suppression effect, followed by Al(OH) 3 powder and dolomite powder. Increasing the inerting ratio progressively suppresses the flame acceleration characteristics of corn starch explosion. The addition of 25 wt.% ABC powder significantly inhibits flame propagation, reducing the average flame propagation velocity by 83.6% and the maximum propagation velocity by 91.7% compared to the uninhibited condition. Compared to Al(OH) 3 and dolomite powder, ABC powder has a lower initial thermal decomposition temperature, a broader pyrolysis temperature range, and greater endothermic efficiency. The thermophysical properties of the powder inhibitors show good consistency with their explosion suppression effectiveness. The inhibitors generate NH 3 , H 2 O, SO 2 , and N 2 , which effectively reduce both the laminar burning velocity and heat release rate of corn starch pyrolysis gases. The competition between H + O 2 = O + OH and H + CH 3 (+M) = CH 4 (+M) dominates the combustion reactions of pyrolytic gases from corn starch. The CO 2 , H 2 O, and NH 3 generated by the thermal decomposition of inhibitors do not alter the fundamental reactions governing combustion. However, the generated SO 2 introduces two additional key inhibitory elementary reactions: H + SO 2 (+M) = HOSO(+M) and H + O 2 (+M) = HO 2 (+M).