ReaxFF Molecular Dynamics Simulation of Hydrogen‐Oxygen Combustion Under Different Initial Pressures

This study employs ReaxFF molecular dynamics simulation based on the CHO‐S22 reactive force field to investigate the effects of pressure variation within the 0.01‐200 atm range on the microscopic reaction mechanism of hydrogen‐oxygen combustion, with particular focus on the pressure dependence of the HO 2 ‐H 2 O 2 ‐OH radical cycle network. By analyzing reactant consumption, radical evolution, product formation, and high‐frequency elementary reactions under different pressures, this research reveals the microscopic mechanisms through which pressure influences hydrogen‐oxygen combustion. The results indicate that: (1) Pressure significantly promotes reactant consumption, with apparent rate constants increasing with rising pressure; (2) Under high‐pressure conditions, OH radical peak concentrations increase and fluctuations intensify; (3) The activity of the HO 2 ‐H 2 O 2 ‐OH cycle network enhances with pressure, and the frequency of H 2 O 2 decomposition reactions increases significantly; (4) High‐frequency elementary reaction pathways remain unchanged, but relative rates undergo systematic variations. This study elucidates the microscopic mechanisms of pressure effects on reaction pathway selection in hydrogen‐oxygen combustion at the molecular level, providing theoretical foundations for optimizing high‐pressure hydrogen‐oxygen combustion system design.