Molecular dynamics study of nano-iron H2O reaction properties and the effect of ether encapsulation in high temperature environment

Abstract

In this study, the reactive molecular dynamics method was employed to investigate the FNP-H₂O, with the parameters analyzed including the proportion of crystalline atoms within the particles, the radial distribution function (RDF) of the key atom pairs, the mean-square displacements (MSD) of the shell and core atoms, the number of H₂O molecules adsorbed on the surface, the number of atomic displacements and the number of key atom pairs in the reaction process during the reaction process of iron nanoparticles (FNPs) of different particle sizes during the aqueous reaction process at different temperatures, and to characterize the FNP-H₂O reaction characteristics were investigated. The findings indicate that decreasing the particle size of FNP facilitates its entry into the pre-ignition state, thereby reducing the ignition delay time. The H₂O molecules adsorbed on the surface of FNP contribute to enhancing the structural stability of the amorphous atoms on the FNP surface before the temperature elevation to 907.2 K. The analysis of the reaction products reveals that Fe-O compounds and Fe-H compounds are the predominant components of the Fe-H₂O reaction products. The ether capping layer’s effect on the ignition mechanism of the FNP-H₂O reaction was also investigated, and the results showed that the ether molecules were directly involved in the whole ignition process of the FNP-H₂O reaction, and had an important influence on the ignition mechanism of the FNP-H₂O reaction. This study has enhanced our comprehension of the FNP-H₂O reaction mechanism and the influence of the ether coating layer, and it has played a guiding role in the subsequent enhancement of the ignition and combustion performance of FNP.