A theoretical study of the anharmonic effect on the important combustion reaction mechanism of NH3/PODE1 mixed fuels

Abstract

The harmonic and anharmonic rate constants, kinetic parameters, and thermodynamic parameters of the combustion mechanism for NH₃/PODE₁ mixed fuels were calculated over a temperature range from 300 K to 4000 K. The influence of both pressure and tunneling effects was thoroughly investigated. In this study, bimolecular reactions show a more pronounced anharmonic effect than unimolecular reactions. Analysis of the frequencies of the reactions studied in this work reveals that the harmonic and anharmonic frequencies are primarily distributed in the high-frequency (2500–4000 cm⁻¹) and low-frequency (0–1500 cm⁻¹) regions. In the reactions of PODE₁ with radicals NO₂ and NH₂, the primary consumption pathway for PODE₁ is the reaction with NH₂. In summary, the computational outcomes have enhanced the accuracy of the combustion reaction mechanism for NH₃/PODE₁ mixed fuels.