Insight into the combustion mechanism of nitroglycerin/nano-aluminum composite materials

Abstract

The ReaxFF-lg is used to simulate the thermal decomposition of the pure nitroglycerin (NG) and nitroglycerin/nano-Al (NG/Al) systems. The simulation results show that the decomposition pathway of NG is the rupture of C–H and O–N bonds. However, the rupture of C–O and N–O bonds of NG is the main decomposition pathway in the NG/Al system. The strong attraction Al to oxygen atoms accelerates NG decomposition. The reaction of the NG/Al system begins on the surface between NG and Al. The surface of aluminum particles is the first to be oxidized. As the temperature increases, O atoms attached to the surface of Al particles penetrate into the aluminum particles. The interior of aluminum particles gradually becomes disordered and fluffy from orderly arrangement. The interaction between O and Al constitutes the early combustion reaction of the NG/Al system, which reduces the production of O-containing intermediates. The attraction of Al to C is greater than that to N at high temperatures, which increases the yield of C-Al cluster and decrease the yield of CO₂ at high temperature. The decomposition of NG/Al is an exothermic reaction without energy barrier. The decomposition of NG needs to overcome an energy barrier of 44.27 kcal/mol. Adiabatic simulation shows that the decomposition rate, heat release rate, and energy release rate of the NG/Al system are significantly higher than those of the NG system. This work presents a comprehensive insight into the interaction mechanism between nano-Al and NG.