Improvement and validation of a detailed reaction mechanism for thermal decomposition of RDX in liquid phase

Khichar, Mayank; Patidar, Lalit; Thynell, Stefan T.

doi:10.1016/j.combustflame.2018.10.005

Cited by 24 publications

(12 citation statements)

References 54 publications

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“…In the later stage, the production of N2 and CO2 are observed, and the overall reactions reach an equilibrium after 100 ps. The production of NO2, NO, HNO2, H2O, and CO2 is also reported in a recent FTIR experiment 40 .The RDX decomposes into NO2, NO and H2O first, and then NO2 and NO starts to decrease after a certain time, while H2O continues to increase. Although the experiments 40 are performed at a lower temperature (e.g.…”

Section: Species Evolution During Rdx Decompositionsupporting

confidence: 71%

Revealing the thermal decomposition mechanism of RDX crystal by a neural network potential

Chu

Chang

Ma³

et al. 2022

Preprint

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A neural network potential (NNP) is developed to investigate the complex reaction dynamics of RDX thermal decomposition. Our NNP model is proven to possess good computational efficiency and retain the ab initio accuracy, which allows the investigation of the entire decomposition process of bulk RDX crystal from an atomic perspective. A series of molecular dynamics (MD) simulations are performed on the NNP to calculate the physical and chemical properties of the RDX crystal. The results show that the NNP can accurately describe the physical properties of RDX crystal, like cell parameters and equation of state. The simulations of RDX thermal decomposition reveal that the NNP could capture the evolution of species at the ab initio accuracy. The complex reaction network was established, and a reaction mechanism of RDX decomposition was provided. The N-N homolysis is the dominant channel, which cannot be observed in previous DFT studies of gas RDX. In addition, the H abstraction reaction by NO2 is found to be the critical pathway for NO and H2O formation, while the HONO elimination is relatively weak. The NNP gives an atomic insight into the complex reaction dynamics of RDX and can be extended to investigate the reaction mechanism of novel energetic materials.

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Section: Species Evolution During Rdx Decompositionsupporting

confidence: 71%

Revealing the thermal decomposition mechanism of RDX crystal by a neural network potential

Chu

Chang

Ma³

et al. 2022

Preprint

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“…Using the couple cluster theory, the E a value of the HONO elimination has been calculated to be lower than that of the N-NO 2 homolytic reaction for RDX [63]. A recent study of the initial decomposition process of liquid RDX has revealed that HONO elimination is likely to be the major decomposition pathway [64].…”

Section: Nitraminesmentioning

confidence: 99%

Models for predicting impact sensitivity of energetic materials based on the trigger linkage hypothesis and Arrhenius kinetics

et al. 2020

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In order to predict the impact sensitivity of high explosives, we designed and evaluated several models based on the trigger linkage hypothesis and the Arrhenius equation. To this effect, we calculated the heat of detonation, temperature of detonation, and bond dissociation energy for 70 energetic molecules. The bond dissociation energy divided by the temperature of detonation proved to be a good predictor of the impact sensitivity of nitroaromatics, with a coefficient of determination (R2) of 0.81. A separate Bayesian analysis gave similar results, taking model complexity into account. For nitramines, there was no relationship between the impact sensitivity and the bond dissociation energy. None of the models studied gave good predictions for the impact sensitivity of liquid nitrate esters. For solid nitrate esters, the bond dissociation energy divided by the temperature of detonation showed promising results (R2 = 0.85), but since this regression was based on only a few data points, it was discredited when model complexity was accounted for by our Bayesian analysis. Since the temperature of detonation correlated with the impact sensitivity for nitroaromatics, nitramines, and nitrate esters, we consider it to be one of the leading predictive factors of impact sensitivity for energetic materials.

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“…However, careful analyses of cook-off experiments have shown that multistep reaction schemes are required to model those response characteristics [5][6][7]. The modelling of propellant combustion processes (especially those containing high explosive constituents HMX and RDX) are quite generally written as containing multiple steps, which are necessary to describe the observed flame structure and its dependence on the confining pressure [8][9][10][11]. Defining the deflagration rates of such materials under moderately high pressures requires an understanding of this staged reaction process (preferably expressed in an Arrhenius form) and how temperature and pressure evolve in the flame structure [12].…”

Section: Introductionmentioning

confidence: 99%

“…However, despite this long-standing interest, there is little that is directly known about these reaction processes in the condensed phase. While the later time (and lower pressure) reactions in propellant combustion flame structures can be well-studied, the initial processes in the condensed phase are more conjectural [8][9][10][11]. The direct observation of reaction processes in solid materials, particularly under shock-loading, has proven to be quite difficult, being frustrated by optical constraints and the rapid reaction rates at appropriate conditions [18][19][20].…”

Section: Introductionmentioning

confidence: 99%

“…The limitations of that work of note here are that: 1) it focused on reactions along the detonation shock Hugoniot curve instead of covering more general reaction conditions; and 2) it neglected differences in chemical isomers in order to simplify the reaction network. This neglects some of the lessons learned in the propellant combustion community where a few chemical processes can serve as controlling steps, and complete knowledge of the reaction system is not necessary to formulate a good approximate solution [8][9][10][11][12]. As understanding the reaction chemistry of high explosives is critical to the development of safer formulations and developing more predictive reactive burn models, the goal of this work is to enable the development of such simplified models.…”

Section: Introductionmentioning

confidence: 99%

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Developing Reaction Chemistry Models from Reactive Molecular Dynamics: TATB

Kober

2022

Propellants Explo Pyrotec

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Reactive Molecular Dynamic (RMD) are used to simulate the cook‐off chemistry of TATB at a variety of fixed density and fixed temperature conditions. The chemical transformations are monitored using a Coordination Geometry Analysis (CGA) approach which tracks which atom types are bonded to each specific atom. This particularly identifies oxidation state changes that occur during the transformations. Correlations between these different chemical changes are identified using a Non‐negative Matrix Factorization (NMF) approach. These identify reduced order chemistry models for the TATB system which contains six components whose concentration profiles are a function of both the temperature and density/pressure. The time histories of these transformations appear to show exponential growth/decay properties that could be fit with Arrhenius rates. These components should form the basis of deflagration rate models for these materials which could then be used in mesoscale simulations to analyze accidental initiation, shock‐to‐detonation and detonation propagation.

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Improvement and validation of a detailed reaction mechanism for thermal decomposition of RDX in liquid phase

Cited by 24 publications

References 54 publications

Revealing the thermal decomposition mechanism of RDX crystal by a neural network potential

Revealing the thermal decomposition mechanism of RDX crystal by a neural network potential

Models for predicting impact sensitivity of energetic materials based on the trigger linkage hypothesis and Arrhenius kinetics

Developing Reaction Chemistry Models from Reactive Molecular Dynamics: TATB

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