Reduction and optimization for combustion mechanism of dimethyl ether–air mixtures

Abstract

AbstractAs an alternative fuel, dimethyl ether (DME) has attracted much attention due to its high efficiency and low emission. In this study, first, a skeletal mechanism of DME is obtained using a directed relation graph with error propagation (DRGEP) and sensitivity analysis (SA). Then the Arrhenius preexponential factors of the selected reactions in the skeletal mechanism are adjusted by the particle swarm optimization (PSO) algorithm to improve the prediction accuracy. Finally, an optimized mechanism with 30 species and 65 elementary reactions is proposed to describe the combustion of DME–air mixtures. This reaction mechanism is validated against the experimental data of ignition delay time, species concentration, and laminar flame speed, covering a wide range of initial temperatures (298–1600 K), pressures (1.0–60 bar), and equivalence ratios (0.5–2.0). Comparing the previous skeletal mechanisms, the optimized mechanism can excellently reproduce the experiment results, especially in the prediction of the ignition delay time of low‐temperature zone and laminar flame speed of high‐pressure conditions. It means that this mechanism corresponds to higher precision and more extensive applicability.