Evaluation of the growth process of soot mass due to changes in hydrogen atomic percentage and external heat flux using molecular dynamics simulation

Abstract

Studying how polycyclic aromatic hydrocarbons transform into soot particles provides insights into factors affecting their formation, composition, and size distribution. Understanding the growth mechanisms of soot from PAHs is crucial for combustion processes and energy efficiency, addressing environmental, health, and energy challenges linked to soot emissions and air pollution. This research aimed to deepen our understanding of these mechanisms by investigating them through molecular dynamics simulations. It used naphthalene as a representative polycyclic aromatic hydrocarbon. The study explored the effect of parameters like hydrogen atomic percentage and heat flux on properties, such as interaction energy, center of mass size, and soot mass size. Results show that increasing hydrogen atomic percentage from 5 % to 25 % increases the interaction energy from −0.15 to −0.12 kcal/mol. At the same time, it reduces the center of mass size from 92.31 to 88.27 Å and the soot mass size from 30.13 to 28.30 Å. Moreover, raising external heat flux from 0.01 to 0.05 W/m2 increases the interaction energy from −0.1 to −0.08 kcal/mol, but increases the center of mass size from 88.49 to 90.18 Å and soot mass size from 28.33 to 30.30 Å after 10 ns.