Investigating the Reaction‐Mechanistic Effects of Nitrogenous Gases on the Thermal High‐Temperature Decomposition of Ammonium Dinitramide‐Based Liquid Propellant: Insights From Reactive Molecular Simulations

ABSTRACT The thermal decomposition of ammonium dinitramide (ADN)‐based liquid propellant (ALP), which is composed of 63.4% ADN, 25.4% H 2 O, and 11.2% CH 3 OH by mass fraction, is significantly influenced by nitrogenous gases. To get a better insight into the effect of nitrogenous gases (N 2 , NH 3 , and NO 2 ) on the thermal decomposition of ALP, the reactive force field ReaxFF‐ l g was employed to describe the bonding and debonding of ALP. Three models (ALP/N 2 , ALP/NH 3 , and ALP/NO 2 ) have been constructed to study the reaction pathways, main products, as well as the influences on mechanisms in the thermal high‐temperature decomposition of ALP at 1000–2500 K. The N─N bond in N 2 was hardly broken to participate in the thermal high‐temperature decomposition of ALP. NH 3 inhibited the decomposition of •NH 4 in ADN, while NO 2 enhanced the dehydrogenation of NH 3 and then accelerated the thermal decomposition of ADN. NH 3 facilitated the generation of H 2 O and reduced the number of •H and •OH, whereas NO 2 inhibited the generation of H 2 O. NO 2 promoted the decomposition of CH 3 OH to produce CO 2 at high temperatures. This study provided an atomic mechanism for the decomposition process of ALP/gases, which would be helpful for further studies on the reaction mechanism of energetic fuels.