Experimental and modeling study on ignition delay times of dimethoxy methane/n-heptane blends

- Ignition delay times of DMM/n-heptane blends were measured.
- A DMM/n-heptane blend model was developed.
- The effects of DMM addition on ignition delay times of DMM/n-heptane blends were analyzed.

Ignition delay times of dimethoxy methane (DMM), n-heptane and DMM/n-heptane mixtures were measured behind reflected shock waves. The experiments were performed at the temperature ranges of 1100-1600 K, at pressures of 2 and 10 atm and equivalence ratios of 0.5, 1.0 and 2.0. A chemical kinetic model for DMM/n-heptane blends was built and validated with the experimental data. The calculations well agreed with the measurements for pure fuel and binary fuels. Based on the experimental and calculated results, effects of pressure, equivalence ratio and DMM blending ratio on ignition delay times were analyzed. Through sensitivity analysis, the most important reactions were found and then the effect of equivalence ratio on ignition delay times was interpreted. The ignition delay times of DMM/n-heptane blends decreased with the addition of DMM. Kinetic analysis revealed that the concentration of radical pool increased with the increase of DMM addition, resulting in an enhancement effect on the chemical reactivity.