Journal Article

Atomistic Insights into the Influence of High Concentration Hsub.2Osub.2/Hsub.2O on Al Nanoparticles Combustion: ReaxFF Molecules Dynamics Simulation

Zhang, Pengtu, Yu, Xindong, Yuan, Shiling, Zhang, Heng

2024

Overview

The combination of Al nanoparticles (ANPs) as fuel and H[sub.2]O[sub.2] as oxidizer is a potential green space propellant. In this research, reactive force field molecular dynamics (ReaxFF-MD) simulations were used to study the influence of water addition on the combustion of Al/H[sub.2]O[sub.2]. The MD results showed that as the percentage of H[sub.2]O increased from 0 to 30%, the number of Al-O bonds on the ANPs decreased, the number of Al-H bonds increased, and the adiabatic flame temperature of the system decreased from 4612 K to 4380 K. Since the Al-O bond is more stable, as the simulation proceeds, the number of Al-O bonds will be significantly higher than that of Al-H and Al-OH bonds, and the Al oxides (Al[O][sub.x]) will be transformed from low to high coordination. Subsequently, the combustion mechanism of the Al/H[sub.2]O[sub.2]/H[sub.2]O system was elaborated from an atomic perspective. Both H[sub.2]O[sub.2] and H[sub.2]O were adsorbed and chemically activated on the surface of ANPs, resulting in molecular decomposition into free radicals, which were then captured by ANPs. H[sub.2] molecules could be released from the ANPs, while O[sub.2] could not be released through this pathway. Finally, it was found that the coverage of the oxide layer reduced the rate of H[sub.2]O[sub.2] consumption and H[sub.2] production significantly, simultaneously preventing the deformation of the Al clusters’ morphology.

• Publisher: MDPI AG
• Subject: Combustion