LES/TPDF investigation of the effects of ambient methanol concentration on pilot fuel ignition characteristics and reaction front structures

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

“…Fourth, methanol has a higher heat of vaporization compared to methane, natural gas, and gasoline, which leads to cooling effects during combustion and consequently, lower charge peak combustion temperature leading to smaller NOx emissions. 4 With relevance to this study, methanol ignition is a particularly sensitive process and several challenges on the smooth ignition of methanol in the DF engines context have been reported in the literature, where for example the crucial role of intake temperature control has been acknowledged in the works by Zou et al 31 , Wang et al 37 , Hu et al 38 and Wang et al 39 Recently, Xu et al 34 investigated effects of increasing the initial ambient methanol-air mixture fraction on ignition at a constant temperature of 900 K. They provided evidence that adding methanol to the ambient may delay the ignition of n -heptane and prolong the transition from low to high-temperature ignition. More recently, we have investigated tri-reactivity ignition of methane/hydrogen 40 and methanol/hydrogen 41 at fixed temperature of 900 K by diesel spray.…”

“…21,22 Using renewable fuels such as methanol in DF CI engines have been studied both experimentally 23–26 and numerically. 27–34 Those studies predominantly focus on the engine geometry and performance, 23,28,30–32 fuel reactivity, 24,27,28 combustion instability, 25 and emissions characteristics. 26,27,29–31,33…”

“…21,22 Using renewable fuels such as methanol in DF CI engines have been studied both experimentally [23][24][25][26] and numerically. [27][28][29][30][31][32][33][34] Those studies predominantly focus on the engine geometry and performance, 23,28,[30][31][32] fuel reactivity, 24,27,28 combustion instability, 25 and emissions characteristics. 26,27,[29][30][31]33 Using methanol over methane, natural gas, and gasoline as the LRF has attracted the interest of DF engines manufacturers over the past few years due to several reasons.…”

A Pressure-Coupled Representative Interactive Linear Eddy Model (RILEM) for Engine Simulations

“…T-PDF is a regime-and modeindependent combustion model that accounts for turbulence chemistry interactions (TCI) via micro-mixing models. While chemistry and advection are treated precisely in T-PDF models, molecular mixing needs to be modeled with so-called micro-mixing models, e.g., Interaction by Exchange with the Mean (IEM) or the Coalescence dispersion (C-D) [8][9][10]. Other models used for both premixed and non-premixed combustion are the Well or Perfectly-stirred reactor (PSR) models and variants such as partially stirred reactor (PaSR) models.…”