Reactive molecular dynamics study of soot formation during ethylene combustion catalyzed by alternating electric fields

The application of external electric fields (E-fields) is an effective method for controlling fuel combustion processes. Reactive molecular dynamics (ReaxFF MD) can effectively simulate the formation and intermediate evolution processes of soot during combustion. The combustion model of 750 ethylene and 450 oxygen is constructed. The E-field amplitude is selected to be 0.1 V/Å, and the alternating period is from 0.1 to 100 ps. The effects of E-field on the growth of soot under different alternating frequencies are simulated by comparing the conditions without E-field and applying unidirectional E-field. The results show that the addition of E-field reduces the molecular weight of the largest molecule in the system. The density of soot is reduced, S/V and H/C become larger, and the system is more dispersed. The E-field increases the activation energy of ethylene pyrolysis, makes the pyrolysis reaction path tilt to C₂H₄ ↔ C₂H₂ + H₂, and delays the formation of the initial C6 ring. The E-field inhibits the growth of soot, and the effect of the E-field is more significant from high frequency to low frequency and then to unidirectional E-field.