Ignition characteristics of lean DME/H₂ mixtures

Ignition delay time of DME/H₂/O₂/Ar was measured under a wide condition using shock tube facility and the ignition process was modeled using Chemkin software. Results show that, when the mole fraction of H₂ X_H2 <80%, ignition delay time shows a typical Arrhenius dependence on temperature and pressure. For 80%< X_H2 <98%, ignition delay time only shows a typical Arrhenius dependence on temperature and ignition delay time at higher pressures gives higher ignition activation energy. However, for X_H2 > 98%, ignition delay time shows a complicated dependence on temperature and pressure. Both measured and calculated results indicate that H₂ addition exhibits the nonlinear influence on the ignition delay time of DME/H₂ mixtures and NUIG C4 model can well predict the experimental data. Chemically interpreting on the above effect was made using small radical mole fraction and normalized consumption of H radicals.