Computational Combustion of Aluminum Nanoparticles with Hydrocarbon Coatings by Reactive Molecular Dynamics Simulations

Aluminum nanoparticles (ANPs) have been considered attractive additives for combustible applications because the ANPs possess a high energy density with an increased burning rate, owing to an increased surface area-to-volume ratio. Unfortunately, use of the ANPs is limited by two factors: (1) ANPs can be readily sintered; and (2) ANPs can be easily oxidized, prior to the combustion process due to their high reactivity, degrading the combustion performance. To address this issue, coating of the ANPs by hydrocarbons has been proposed. The previous studies reported that the hydrocarbon-coated ANPs are less reactive at low temperatures, and they became susceptible to the oxidation at higher temperatures, suggesting that the hydrocarbon coating is essential for the ANPs to be used combustible materials. However, fundamental understanding of sintering and thermal behaviors of the hydrocarbon-coated ANPs has yet to be achieved. Here we perform reactive molecular dynamics (RMD) simulations to investigate effects of hydrocarbon coating on the combustion process of the ANPs including sintering and oxidation processes. Using RMD simulations, detailed reaction steps for the combustion process of uncoated and hydrocarbon coated ANPs would be studied at a molecular level. Our RMD simulations will help guide an experimental design of ANPs-based solid rocket fuels, thus providing a valuable input for the community of aerospace applications.