On the modeling of hydrocarbon combustion in external electric fields with reactive molecular dynamics
File(s)
Published version
Author(s)
Lalli, Navraj S
Giusti, Andrea
Type
Journal Article
Abstract
The use of electric fields may provide a mechanism to enable fuel-flexible technologies in aviation. The development of such technologies requires methodologies able to accurately quantify electric field effects on chemical reactions at the molecular level. This work provides a comprehensive assessment of methodologies used in the framework of reactive molecular dynamics (MD) with the reactive force field ReaxFF. The focus is on the computation of atomic charges, the method used for equilibration, and the use of global thermostats for hydrocarbon combustion in an external electric field. The charge equilibration method (QEq) and the charge transfer with polarization current equilibration method (QTPIE) were analyzed for the computation of atomic charges. For the fuel–oxygen system investigated, QEq leads to molecules with a sizable spurious net charge. QTPIE leads to more accurate molecular charges but at the cost of underestimating some atomic charges. This leads to faster combustion kinetics with QEq compared with QTPIE. A two-step equilibration procedure provides a more equilibrated system compared to widely used equilibration procedures. Furthermore, using a global thermostat with an external electric field results in an artificial reduction in fuel and oxygen first-order reaction rates. These artificial effects can be avoided by not using a thermostat, but at the expense of electric-field-induced heating. Applying an external electric field without a global thermostat accelerates combustion much more with QEq compared with QTPIE, due to the larger charges predicted by QEq. This study reveals several simulation artifacts that affect reactive MD of fuel combustion and contributes toward the more accurate modeling of fuel combustion in external electric fields.
Date Issued
2025-05-07
Date Acceptance
2025-04-09
Citation
Journal of Chemical Physics, 2025, 162 (17)
ISSN
0021-9606
Publisher
American Institute of Physics
Journal / Book Title
Journal of Chemical Physics
Volume
162
Issue
17
Copyright Statement
© 2025 Author(s). All article content, except where otherwise noted, is licensed under a Creative Commons Attribution (CC BY) license (https://creativecommons.org/licenses/by/4.0/).
License URL
Identifier
10.1063/5.0264365
Publication Status
Published
Article Number
174311
Date Publish Online
2025-05-02