On the surface chemisorption of oxidizing fine iron particles: Insights gained from molecular dynamics simulations

Effect of Fe–O ReaxFF on Liquid Iron Oxide Properties Derived from Reactive Molecular Dynamics

“…To assess the impact of the MAC and TAC obtained with the different ReaxFF parameter sets, the single iron particle model, as described by Thijs et al, 14 is used. In the study of Thijs et al, 14 it was assumed that the iron oxide particle consists of a homogeneous mixture. However, as previously discussed, the equilibrium phase diagram 37 describes that liquid iron (L1) and liquid iron oxide (L2) do not mix in the region between 0.013 < Z O < 0.506 at 2000 K. Furthermore, the experimental observations of Muller et al 20 seem to indicate a complex oxidation process in the liquid, for instance, with L1 being also present at the particle surface and, under certain circumstances, miscibility between the phases L1 and L2.…”

“…Density. In the study of Thijs et al, 14 the effects of ReaxFF2010-full and ReaxFF2016 on the density of solid and liquid FeO and on magnetite (solid Fe 3 O 4 ) were investigated. It was found that at high temperatures, the density of FeO predicted by ReaxFF-2016 agreed better with experimental results, while at solid-phase temperatures, ReaxFF-2010 agreed better with experiments, and ReaxFF2016 was not able to capture the phase change.…”

“…To design and improve real-world iron-fuel burners, an in-depth understanding of the fundamentals underlying the combustion of single iron particles is required. In the past few years, the number of more detailed experimental − and theoretical studies − regarding the combustion of single iron particles has increased drastically. In this early research on iron particle combustion, a good agreement between experiments and theoretical models for low gas temperature (300 K) and low oxygen concentration cases (up to X O2 = 0.21) was obtained.…”

“…For the specific case of iron, (reactive) molecular dynamics simulations have been used for various applications: to determine the material properties of pure liquid iron, the oxidation of nanoparticles and surfaces with oxygen, − the oxidation of Fe with CO 2 , and H 2 O, and also for the oxidation of alloys . In the study of Thijs et al reactive MD simulations were used to investigate the thermal and mass accommodation coefficients (TAC and MAC, respectively) for the combination of high-temperature iron­(-oxide) and air. It should be noted that these (reactive) MD simulation results are to some extent limited by the accuracy and availability of the (reactive) force fields.…”

“…Both MAC and TAC are critical parameters that directly impact the oxidation efficiency and heat transfer efficiency during iron particle combustion, respectively. The impact of MAC and TAC values derived from different reactive force fields is assessed using the single iron particle model outlined by Thijs et al 14 The paper is organized as follows. Section 2 describes the research strategy, the methodology used for the molecular dynamics simulations, and the methodology for the thermodynamic calculations.…”