ReaxFF molecular dynamics simulation on the combustion mechanism of toluene/ethanol/n-heptane mixed fuel

The addition of ethanol and toluene to diesel fuel serves as an effective approach to mitigate engine knock. In this work, we employed ReaxFF molecular dynamics simulations to investigate the oxidation of toluene, ethanol, and n-heptane mixed fuels. Results show that toluene, ethanol, and 60.12 % of n-heptane molecules initiate dehydrogenation via active species such as O-2, OH, HO2, etc. The initial decomposition mechanisms of the remaining n-heptane molecules involve the fission of Csbnd C bonds and direct dehydrogenation reactions. The formation of intermediate C2H4 primarily occurs via beta-cleavage of saturated alkyl radicals with higher carbon atom numbers. The products CO and CO2 molecules strongly depend on the concentrations of C2H4 and CH3. Notably, the incorporation of ethanol/toluene in the system diminishes the presence of OH, thereby decreasing the consumption of C2H4 by OH. The activation energy values (43.36 similar to 45.19 kcal mol(-1)) align well with experimental data.