The role of DME addition on the evolution of soot and soot precursors in laminar ethylene jet flames

How do the oxygenated functional groups in ether, carbonate and alcohol affect soot formation in Jet A2 diffusion flames?

“…The HAMA mechanism can occur favourably on alkyl chains [119,120], which could be significant in Jet A2 because half of it is composed of paraffins [79]. The importance of methyl radicals in soot precursor and soot formation has also been shown in dimethyl ether [121][122][123][124] and methanol [23,57] flames. In the current investigation, the DMM blend would produce more methyl radicals than the PODE 3 blend at the same O/C ratio because DMM is the shorter poly-ether.…”

Feasibility on equivalence ratio measurement via OH*, CH*, and C2* chemiluminescence and study of soot emissions in co-flow non-premixed DME/C1–C2 hydrocarbon flames

“…Most of these studies found a considerable impact of fuel structure on PAH and soot formation. Although several researchers have added DME to the combustion of different hydrocarbon biofuels in non-premixed flames and studied the impact on soot and PAH (McEnally and Pfefferle, 2007;Yoon et al, 2008;Bennett et al, 2009;Choi et al, 2011;Liu et al, 2011;Sirignano et al, 2014;Choi et al, 2015;Li et al, 2018;Ahmed et al, 2021;Serwin and Karataş, 2021;Abu Saleh et al, 2022), different conclusions were reached about the relationship between DME addition and soot emissions. Details of these previous studies are presented in Table 1.…”

“…Details of these previous studies are presented in Table 1. The majority (McEnally and Pfefferle, 2007;Yoon et al, 2008;Bennett et al, 2009;Liu et al, 2011;Ahmed et al, 2021) studied DME/ethylene mixtures and found that a small (5-40%vol) addition of DME to ethylene fuel resulted in increased soot formation. This contradicts the finding of reduced soot emission benefits from DME/diesel blend conducted in a direct injection engine (Ying et al, 2006) and the finding in DME/alkane blends, where DME blending with methane, ethane, and propane showed decreased soot and PAH formation across all DME mixture ratios (Yoon et al, 2008).…”

On the sudden reversal of soot formation by oxygen addition in DME flames

“…Diverse studies [4,[6][7][8] have shown that the addition of small amounts of DME to methane, ethylene, ethane, and propane flames create a synergetic effect that enhances soot production due to its chemical effects, but further additions radically reduce soot concentration. Despite the important efforts in the literature to scrutinize DME combustion, DME's characteristics as a single fuel in flames have not been deeply studied, especially for laminar configurations.…”