Development of a Reduced Methane-Hydrogen-Polyoxymethylene Dimethyl Ether Mechanism under Engine-Relevant Conditions

Polyoxymethylene dimethyl ethers (PODE ) have a high cetane number and a high oxygen content, which can effectively reduce the soot emission. In this study, PODE₃, methane, and hydrogen were used as the characterization fuel. First, the detailed reaction mechanism of PODE₃ and GRI-Mech 3.0 was reduced under engine-relevant conditions by using the reduced methods of the direct relation graph, the directed relation graph with error propagation, the sensitivity analysis, and the reaction pathway analysis. Then, the simplified PODE₃ and methane-hydrogen mechanism were coupled and optimized. Finally, the simplified chemical kinetics mechanism of methane-hydrogen-PODE₃ (67 species, 260 reactions) was developed. After that, the methane-hydrogen-PODE₃ mechanism for methane/hydrogen/PODE₃ blend combustion was established, and experimental verification was performed against ignition delay times, laminar flame speeds, and premixed flame species profiles, which showed a good agreement between the predicted and experimental data. Finally, the current mechanism was found to have high reliability and can be coupled to computational fluid dynamics.