ReaxFF simulations on the combustion of Al and n-butanol nanofluid

Cheng, Yu-Xiao; Zhao, Ying; Zhao, Fengqi; Xu, Shidang; Ju, Xue‐Hai; Ye, Caichao

doi:10.1016/j.fuel.2022.125465

Cited by 19 publications

(4 citation statements)

References 59 publications

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“…The MD simulation is highly dependent on the potential energy surface, which can be determined by ab initio calculations or an empirical method. The empirical potential approach (e.g., ReaxFF , ) has been widely used in investigating the initial decomposition pathways of energetic materials induced by thermal and mechanical stimulation. − Recently, MD simulations have been performed to reveal the atomic insights behind the mechanical and structural properties of AP. Yeh and Andzelm investigated the structural and energetic properties of the ammonium perchlorate (AP) crystal in bulk and at interfaces using molecular dynamics (MD) simulations.…”

Section: Introductionmentioning

confidence: 99%

Reaction Network of Ammonium Perchlorate (AP) Decomposition: The Missing Piece from Atomic Simulations

Chu

Wen

Fu³

et al. 2023

J. Phys. Chem. C

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The decomposition network of ammonium perchlorate (AP) is essential for combustion performance and safety of solid propellants, while the detailed reaction pathway during thermolysis is far from clear due to the ultrafast and complex reactions involved. Herein, we present direct atomic simulations of AP thermal decomposition and propose a detailed decomposition network to fill the missing piece in the kinetic models by using a neural network model derived from ab initio calculations. The proton transfer is the dominant channel (NH 4 + ClO 4 → NH 3 + HClO 4 ), which is also observed in previous mass spectra experiments. In addition, gas products from decomposition play a critical role in promoting the decomposition of solid AP. For example, the H abstraction reaction by OH is found to be a critical pathway for AP decomposition. These simulations provide atomic insights into the complex reaction dynamics of AP and can be extended to investigate the reaction mechanism of novel energetic materials.

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Section: Introductionmentioning

confidence: 99%

Reaction Network of Ammonium Perchlorate (AP) Decomposition: The Missing Piece from Atomic Simulations

Chu

Wen

Fu³

et al. 2023

J. Phys. Chem. C

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“…20 The Al/C/H/O force field used in this study was taken from Hong et al, 29 which was optimized against quantum mechanics data as well as experimental data, 29 and has been employed by others for the simulation of Al nanoparticles in many scenarios similar to this work, such as the carbon coating on Al nanoparticles, 29 the combustion of Al nanoaggregates in high-speed flows, 10 the interaction between graphene oxides and Al nanoparticles, 17 and the combustion of Al/n-butanol nanofluid. 30 2.2. Simulation Details.…”

Section: Methodsmentioning

confidence: 99%

Molecular Dynamics Study on the Capture of Aluminum Particles by Carbon Fibers during the Propagation of Aluminum-Based Energetics

Zhou,

Zachariah

2024

Energy Fuels

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Previous experimental results have shown that carbon fibers (CF) can significantly promote the propagation of aluminum-based nanothermites and propellants. To explore the mechanism of this enhancement, the interaction of 4−6 nm Al/ Al 2 O 3 core−shell nanoparticles with a carbon fiber surface at 1000−2500 K is investigated by reactive molecular dynamics. The results show that regardless of the temperature, Al nanoparticles adhere to the surface of the carbon fiber upon interception. At 1000 K, Al nanoparticles adhere through physisorption; however, with increasing temperature, a transition to chemical bonding occurs, marked by the formation of Al−C bonds and the enhanced binding energy between the particle and the surface. The binding energy at 2500 K is 2 orders of magnitude higher than that at 1000 K. Larger Al particles are found to have a stronger binding energy at the same temperature. The sintering of two Al nanoparticles on the surface of the carbon fiber is also examined. Al nanoparticles that are bound to a carbon fiber surface have much lower sintering rates (i.e., the particle shrinkage ratio can be decreased by up to ∼90%, and the particle surface loss ratio can be decreased by up to ∼50%). The discrepancy becomes notably more pronounced at elevated temperatures, where the sintering of Al nanoparticles in the aerosol phase is very fast. The effect of CF addition is to trap burning particles close to the burning surface for a longer time, thereby enhancing heat feedback. This simulation work provides an atomisticlevel explanation for our previous experimental works (

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“…Its reactive force field potential function is derived from experimental data and density functional theory, so the accuracy is close to quantum computation and does not require the predetermination of chemical reaction paths in the system [ 30 ]. ReaxFF MD has been widely used in the study of pyrolysis [ 31 ], combustion [ 32 ], explosions [ 33 ], oxidation [ 34 ], catalytic [ 35 ], and other systems involving physical chemistry. It provides a promising means of exploring the chemical behavior of complex molecular systems.…”

Section: Methodsmentioning

confidence: 99%

Effect of Equivalence Ratio on Pollutant Formation in CH4O/H2/NH3 Blend Combustion

Sun,

Liu,

et al. 2023

Molecules

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This paper investigates the effect of equivalence ratio on pollutant formation characteristics of CH4O/H2/NH3 ternary fuel combustion and analyzes the pollutant formation mechanisms of CO, CO2, and NOX at the molecular level. It was found that lowering the equivalence ratio accelerates the decomposition of CH4O, H2, and NH3 in general. The fastest rate of consumption of each fuel was found at φ = 0.33, while the rates of CH4O and NH3 decomposition were similar for the φ = 0.66 and φ = 0.4. CO shows an inverted U-shaped trend with time, and peaks at φ = 0.5. The rate and amount of CO2 formation are inversely proportional to the equivalence ratio. The effect of equivalence ratio on CO2 is obvious when φ > 0.5. NO2 is the main component of NOX. When φ < 0.66, NOX shows a continuous increasing trend, while when φ ≥ 0.66, NOX shows an increasing and then stabilizing trend. Reaction path analysis showed that intermediates such as CH3 and CH4 were added to the CH4O to CH2O conversion stage as the equivalence ratio decreased with φ ≥ 0.5. New pathways, CH4O→CH3→CH2O and CH4O→CH3→CH4→CH2O, were added. At φ ≤ 0.5, new intermediates CHO2 and CH2O2 were added to the CH2O to CO2 conversion stage, and new pathways are added: CH2O→CO→CHO2→CO2, CH2O→CO→CO2, CH2O→CHO→CO→CHO2→CO2, and CH2O→CH2O2→CO2. The reduction in the number of radical reactions required for the conversion of NH3 to NO from five to two directly contributes to the large amount of NOX formation. Equivalent ratios from 1 to 0.33 corresponded to 12%, 21.4%, 34%, 46.95%, and 48.86% of NO2 remaining, respectively. This is due to the fact that as the equivalence ratio decreases, more O2 collides to form OH and some of the O2 is directly involved in the reaction forming NO2.

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ReaxFF simulations on the combustion of Al and n-butanol nanofluid

Cited by 19 publications

References 59 publications

Reaction Network of Ammonium Perchlorate (AP) Decomposition: The Missing Piece from Atomic Simulations

Reaction Network of Ammonium Perchlorate (AP) Decomposition: The Missing Piece from Atomic Simulations

Molecular Dynamics Study on the Capture of Aluminum Particles by Carbon Fibers during the Propagation of Aluminum-Based Energetics

Effect of Equivalence Ratio on Pollutant Formation in CH4O/H2/NH3 Blend Combustion

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