| In order to improve fuel economy and reduce harmful emissions significantly, it is very important to comprehense deeply and master the ignition process and the oxidation kinetic mechanisms of hydrocarbon fuels. Currently, Liquefied Petroleum Gas and Dimethyl Ether have become very important alternative fuels, so the shock tube experimental system and CHEMKIN software were used to study the ignition characteristics of Dimethyl Ether and Liquefied Petroleum Gas/ Dimethyl Ether blends, which is used to improve HCCI combustion characteristics, broaden the load range of HCCI combustion and reduce NOX and soot emissions at the same time. In this study, the chemical kinetic mechanism of LPG/DME blends was established, and its predictions agree well with experimental data.Then this mechanism of blends were used to make sensitivity analysis and the reaction pathway analysis.Firstly, ignition delay times of DME were measured in a shock tube at different temperatures, and modeling study was conducted by using the mechanism of Zhao. The conclusions are as follows:ignition delay times are prolonged with equivalence ratio decreasing, the sensitivity of equivalence ratio drops at high temperature phase; ignition delay times are shortened with the pressure increasing.The most sensitive reactions are mainly involved in small molecules and the effect of the big molecule reactions get stronger with temperature increasing.The ignition delay times of LPG/DME blends were measured in a shock tube. The reaction pathway analysis and sensitivity analysis were performed by using the mechanism of blends that established in this study. The conclusions are as follows:The increasing DME blending ratio shortens ignition delay times, and DME compete with propane for small molecules. Pathway analysis revealed that the main reaction pathways are substantially the same at different blending ratios, and the H-abstraction reaction still plays the dominant role. |
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