Combustion Characteristics of DME/Air Premixed Mixtures

Combustion characteristics of dimethyl ether/air premixed mixtures were studied in a constant volume bomb under various equivalence ratios and initial pressures. Meanwhile, a two-zone model was proposed for predicting combustion parameters based on pressure data. The study shows that the mixtures with the stoichiometric equivalence ratio have the maximum normalized mass burning rate and maximum pressure rise rate. For the lean mixtures and the mixture with the stoichiometric equivalence ratio, the flame propagation speed increases with the decrease of initial pressure, while for the rich mixture, the flame propagation speed decreases with the decrease of initial pressure. The maximum combustion pressure occurs at the stoichiometric equivalence ratio regardless of initial pressure. For a given equivalence ratio, the maximum combustion pressure increases remarkably with the increase of initial pressure. The shortest combustion duration and flame development duration occur at the stoichiometric equivalence ratio and remain almost unchanged with the investigated initial pressures.