Study on combustion characteristics of dimethyl ether and hydrogen blends based on a rapid compression machine

Effects of the hydrogen blending ratio, equivalence ratio and compressed pressure on the ignition delay time of DME/H₂/O₂/N₂ mixture are investigated using a rapid compression machine (RCM) at compressed temperature of 650~830 K, compressed pressure of 1.94~2.45 MPa, equivalence ratio of 0.83~1.25 and nitrogen dilution ratio of 89.74% in this study. Kinetics model was built to predict the ignition delay time and simulate the combustion process. The results show that: with the increasing hydrogen blending ratio, there is only little change about the first stage ignition delay time of DME/H₂/O₂/N₂ mixture, and the total ignition delay time extends; with the increasing equivalence ratio and compressed pressure, the first stage ignition delay time of the DME/H₂/O₂/N₂ mixture only has little change, and the total ignition delay time shortens.