Study on chemical kinetic mechanism of methanol/diesel surrogate fuel

In order to study the combustion process of diesel/methanol dual-fuel (DMDF) in the engine cylinder, a methanol/diesel surrogate fuel reaction mechanism was constructed, which includes 101 species and 288 reactions. This study optimized the diesel/methanol combustion mechanism by adjusting the rate constants of key reactions based on ignition delay sensitivity analysis. A zero-dimensional model was used to validate the ignition delay time (IDT), laminar flame speed (LFS), and concentration of key species under various conditions for the dual-fuel mechanism. Furthermore, the methanol/diesel surrogate fuel mechanism was coupled with multidimensional computational fluid dynamics (CFD) to validate the combustion process within the engine cylinder under both pure diesel and DMDF modes. The results show that the combustion mechanism of methanol/diesel surrogate fuel is highly consistent with the experimental data in terms of IDT, LFS, and concentration of key species. In addition, by combining the combustion mechanism with CFD simulation, the simulation results of cylinder pressure, heat release rate, and formaldehyde, acetaldehyde, ethylene, and butadiene emissions are consistent with the experimental data, further verifying the reliability of the methanol/diesel surrogate fuel mechanism. The constructed DM mechanism can provide a theoretical basis for the development and application of clean, low-carbon alternative fuels in engines.