Atomic insights into the combustion mechanism of DME/NH3 mixtures: A combined ReaxFF-MD and DFT study
Shoutong Diao, Haitao Li, Minggao Yu
Abstract
Ammonia is gradually becoming a hot research topic as an important hydrogen energy carrier and carbon-free fuel. In this study, we performed detailed numerical simulations on the combustion mechanism of DME/NH 3 mixtures through reactive force field molecular dynamics simulations and density functional theory calculations. The results showed that the system temperature is positively correlated with the reaction rate and NO x production, and ammonia is consumed significantly earlier than DME. The ammonia molecules were always consumed before the DME molecules. An increase in temperature from 2500 K to 3500 K resulted in a significant decrease in the time for complete consumption of the DME molecules, from 450 ps to 68 ps. Additionally, in the initial reaction process between DME and ammonia, C 2 H 6 O => CH 3 O + CH 3 serves as the dominant reaction of DME. Ammonia is mainly consumed by oxidation via reactions NH 3 + HO 2 => NH 2 + H 2 O 2 and NH 3 + O 2 => NH 2 + H 2 O. Eventually, density functional theory utilized to further explain the intrinsic mechanism of the initial reaction pathways and the molecular active reaction sites. Overall, the results of this work would provide theoretical basis for exploring the chemical reaction kinetic mechanism of DME/NH 3 blended fuels.