Numerical Study of H 2 O Dilution Effect on Laminar Combustion Characteristics of Premixed CH 3 OH/Air Flame

This study systematically investigates the effects of equivalence ratio, H 2 O dilution, and initial temperature on the laminar combustion characteristics of methanol/air flames through numerical simulations. The validation demonstrated that the San Diego mechanism exhibits superior predictive capability in calculating the laminar burning velocity (LBV) of the methanol/air flame. The findings of the study indicated a negative correlation between the LBV, thermal diffusivity, and adiabatic flame temperature of the premixed methanol/air flame and the H 2 O volume fraction, and a positive correlation with the initial temperature. As the H 2 O volume fraction increased, the LBV in the mixture exhibited a corresponding decline, reaching 49.18, 47.18, 45.43, 43.16, and 39.28 cm/s, respectively. The maximum exothermic heat released from the gas‐phase reaction and the reactive radical (H, O, and OH) mole fractions are diminished in the presence of aqueous diluents, resulting in reduced temperatures and decreased fuel reactivity, which consequently decelerates the reaction rate. An increase in the H 2 O volume fraction has been demonstrated to contribute to the hydrodynamic stability of the fluid during methanol combustion, as well as to a reduction in CO emissions.