Kinetic modeling study of homogeneous ignition of dimethyl ether/hydrogen and dimethyl ether/methane

Homogeneous ignition combustion of different proportion DME/H2 and DME/CH4 blend fuels in the air is investigated through the numerical simulation with the detailed chemistry at the low and high temperatures in this paper. The emphasis is the assessment of the kinetic effects involved in the ignition combustion of DME/H2 and DME/CH4 dual-fuel. It is found that the homogeneous ignition process has a clear distinction at the different temperatures. At the low temperature (900 K), the ignition delay times of DME/H2 blends and DME/CH4 blends both show an increase with a decrease of the DME blending ratio; furthermore, it is observed that CH4 addition is more effective than H2 addition in terms of delaying the DME homogeneous ignition due to the stable molecular structure of CH4. At the high temperature (1400 K), with the decrease of DME blending ratio, the ignition delay time of DME/CH4 blends is still increased, whereas, the ignition delay time of DME/H2 blends is shortened. Sensitivity analysis, reaction path analysis and main pollutant species calculation are carried out and key elementary reactions involved in homogeneous ignition of DME/H2 and DME/CH4 dual fuel are also identified in this paper.