ReaxFF based molecular dynamics simulations of ignition front propagation in hydrocarbon/oxygen mixtures under high temperature and pressure conditions

2017 ◽  
Vol 19 (7) ◽  
pp. 5004-5017 ◽  
Author(s):  
Chowdhury Ashraf ◽  
Abhishek Jain ◽  
Yuan Xuan ◽  
Adri C. T. van Duin
Keyword(s):  
Front Propagation ◽  
Field Method ◽  
Reactive Force ◽  
Front Speed ◽  
High Temperature And Pressure ◽  
Reaxff Reactive Force Field ◽  
Temperature And Pressure ◽  
Dynamics Simulations ◽  
Ignition Front ◽  
First Time

This work investigates the ignition front speed of hydrocarbon fuels at atomistic level for the first time using the ReaxFF reactive force field method.

scholarly journals Lightning-induced high temperature and pressure microstructures in surface and subsurface fulgurites

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Li-Wei Kuo ◽  
Steven A. F. Smith ◽  
Chien-Chih Chen ◽  
Ching-Shun Ku ◽  
Ching-Yu Chiang ◽  
...  
Keyword(s):  
High Pressure ◽  
High Temperature ◽  
Reference Sample ◽  
Near Surface ◽  
Landing Point ◽  
High Pressure Metamorphism ◽  
High Temperature And Pressure ◽  
Cloud To Ground Lightning ◽  
Temperature And Pressure ◽  
First Time

AbstractCloud-to-ground lightning causes both high-temperature and high-pressure metamorphism of rocks, forming rock fulgurite. We demonstrate that a range of microstructural features indicative of high temperatures and pressures can form in fulgurites at the surface and in fractures up to several meters below the surface. In comparison to a granite reference sample collected from a borehole at a depth of 138 m, microstructures in both the surface and fracture fulgurite are characterized by: (i) the presence of glass, (ii) a phase transformation in K-feldspar with the presence of exsolution lamellae of plagioclase, and (iii) high residual stresses up to 1.5 GPa. Since this is the first time that fracture-related fulgurite has been described, we also carried out a 1-D numerical model to investigate the processes by which these can form. The model shows that the electric current density in fractures up to 40 m from the landing point can be as high as that on the surface, providing an explanation for the occurrence of fracture-related fulgurites. Our work broadens the near-surface environments in which rock fulgurite has been reported, and provides a detailed description of microstructures that can be compared to those formed during other types of extreme metamorphic events.

Molecular dynamics approach for crystal structures of methane A and B

2017 ◽  
Vol 28 (04) ◽  
pp. 1750048 ◽  
Author(s):  
César G. Galván ◽  
José M. Cabrera-Trujillo ◽  
Ivonne J. Hernández-Hernández ◽  
Luis A. Pérez
Keyword(s):  
Molecular Dynamics ◽  
High Pressures ◽  
Force Fields ◽  
Recent Experimental Data ◽  
Reactive Force ◽  
Carbon Structures ◽  
Reactive Force Fields ◽  
Temperature And Pressure ◽  
Dynamics Simulations ◽  
Good Agreement

The carbon structures of phases A and B of methane are investigated through classical molecular dynamics simulations using optimized potentials for liquid simulations all-atom force fields as well as ReaxFF reactive force fields. Both final thermodynamic states were obtained by the proper ramping of temperature and pressure through well-known regions of methane’s phase diagram using the isothermal–isobaric (NPT) ensemble. Our calculated structures are in good agreement with very recent experimental data. The knowledge of these phases is the basis for the study of methane at high pressures.

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