Combustion chemistry of n-heptane/ethanol blends: a ReaxFF study

ABSTRACT

The effect of ethanol on n-heptane oxidation was studied using the reactive molecular dynamics (RMD) method. With different ethanol concentrations, simulations were performed under fuel-rich conditions from 2000 −2500 K. The results showed that ethanol addition had little effect on the n-heptane oxidation rate. However, the presence of ethanol inhibited the formation of major species (e.g. Ethylene and Formaldehyde) in different ways. The amount of C₂H₄ during n-heptane oxidation was clearly greater than that during n-heptane/ethanol oxidation, indicating that the dissociation of ethanol (C₂H₅OH →C₂H₄ + H₂O) was not an effective pathway to produce C₂H₄. Conversely, ethanol addition had a two-fold impact on CH₂O formation at high temperatures. Ethanol promoted the formation of the C₂H₅O radical, which was the main intermediate to produce CH₂O. However, ethanol addition reduced the amount of n-heptane in the system, lowered the rate of CH₃ radical formation, and subsequently decreased CH₂O formation, consistent with previous experiments.

KEYWORDS:

• N-heptane
• ethanol
• oxidation
• reactive molecular dynamics

Acknowledgement

This work was supported by the National Natural Science Foundation of China (No.21403221 and 91441106).

Disclosure statement

No potential conflict of interest was reported by the author(s).

Additional information

Funding

This work was supported by National Natural Science Foundation of China: [Grant Number 21403221].