In this study, ignition delay times of liquified petroleum gas (LPG)/dimethyl ether (DME) (LPG consists of C 3 H 8 and C 4 H 10 in this work) were measured in a shock tube at different DME blending ratios (0%, 10%, 30%, and 50%), pressures (5, 10, and 15 atm), temperatures (1100−1500 K), and equivalence ratios (0.5, 1.0, and 1.5). The chemical kinetic mechanism of LPG/DME was established based on Lawrence Livermore National Laboratory's C1−C4 chemical kinetic mechanism (Combust. Flame 1998, 114, 192−213) and Zhao's DME chemical kinetic mechanism (Int. J. Chem. Kinet. 2008, 40, 1−18), and its predictions agree well with experimental data. A sensitivity analysis and a reaction pathway analysis were conducted using CHEMKIN-PRO to study the impact of DME addition on the ignition and combustion process. The experimental results show that the ignition delay times of LPG/DME change linearly with increasing DME blending ratios. The sensitivity analysis shows that the number of major promoting reactions for mixtures increases, including H-abstraction and decomposition of CH 3 OCH 3 , while the sensitivity factors of the H-abstraction and the decomposition of C 3 H 8 (reactions R115, R120, and R125) decrease with increasing DME blending ratios. The reaction pathway analysis indicates that the H-abstraction reactions play a dominant role, and the contribution rate of OH to H-abstraction increases, while that of H-radical decreases slightly in the oxidation of C 3 H 8 and C 4 H 10 with the increasing proportion of DME in the LPG/DME mixtures. Further analysis shows that although the growth rate of H before ignition is LPG100 > LPG50 > DME, reaction R22 in the oxidation process of mixtures makes OH accumulate rapidly in a short time, resulting in a much higher peak concentration of OH than that of H; therefore, the ignition delay times of mixtures are shorter than those of neat LPG.
The ignition delay times of different n-butanol/dimethyl ether (DME) mixtures (DME mole ratios of 100%, 80%, 60%, 40%, and 0%) were studied behind reflected shock waves at equivalence ratios of 0.5, 1.0, and 1.5; pressures of 6.0, 10, and 15 bar; temperatures of 1150−1650 K. The effects of a carrier gas (nitrogen or argon) on the ignition delay times of single and blended fuels were also studied. The chemical kinetic mechanism of DME/n-butanol was established based on Zhao's DME chemical kinetic mechanism (Int. J. Chem. Kinet. 2008, 40, 1−18) and Strathy's n-butanol chemical kinetic mechanism (Combust. Flame 2012, 159, 2028−2055, which can accurately predict the ignition delay times of both single and blended fuels. Experimental results show that the ignition delay time of DME is longer than that of n-butanol when the temperature is high (>1150 k) and that the ignition delays of blended fuels increase with an increased blending ratio of DME. However, the relationship between ignition delay time and the blending ratio is nonlinear. The main factor affecting the blended fuel's ignition delay is temperature, and with every 200 °C increase in temperature, the ignition delay times is reduced by an order of magnitude. Additionally, pressure has a large effect on the ignition delay times. The results of reaction path analysis of blended fuels show that with an increasing DME blending ratio, the contribution rate of OH-radicals to H-abstraction decreases during the oxidation of n-butanol, and the contribution rate of H-radicals to H-abstraction of n-butanol increases slightly. However, with an increasing DME blending ratio, the pyrolysis of DME decreases, but the contribution rate of CH 3 and OH to the Habstraction of DME increases.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
customersupport@researchsolutions.com
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
Copyright © 2024 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.