Large-eddy simulation of diesel pilot spray ignition in lean methane-air and methanol-air mixtures at different ambient temperatures

In dual-fuel compression-ignition engines, replacing common fuels such as methane with renewable and widely available methanol is desirable. However, a fine-grained understanding of diesel/methanol ignition compared to diesel/methane lacking. Here, large-eddy simulation (LES) coupled finite rate chemistry utilized study diesel spray-assisted methanol. A surrogate fuel ( n-dodecane) spray injected into ambient methane-air or methanol-air mixtures at fixed lean equivalence ratio [Formula: see text] = 0.5 various temperatures ([Formula: 900, 950, 1000 K). The main objectives are (1) compare the characteristics different text], (2) explore relative importance low-temperature (LTC) high-temperature (HTC), (3) identify key differences between oxidation reactions n-dodecane Results from homogeneous reactor calculations well 3 + LES reported. For both DF configurations, increasing leads earlier first- second-stage ignition. Methanol/ mixture observed have longer delay time (IDT) methane/ n-dodecane, for example ≈ three times IDT 950 K. While response systematic robust, window n-dodecane/methanol very narrow investigated conditions, only K robust observed. K, autoignites before while 900 full not after ms, although first-stage methanol, LTC considerably weaker than in fully igniting cases, heat release map analysis demonstrates dominant contribution HTC total Reaction sensitivity shows that stronger consumption OH radicals by further n-dodecane/methanol. Finally, simple novel approach developed estimate reacting using zero-dimensional weighted residence non-reacting data.