Ignition delay times of CH4/CH3Cl/O2/Ar mixtures are measured using a shock tube at 1350–1950 K and 4–18 atm. Equivalence ratios of 0.5 and 1 and CH3Cl blending ratios ranging from 0 to 1 are explored. Correlations for the measured delay times are obtained through multiple linear regression. Increasing the blending ratio facilitates ignition, but this effect becomes saturated at a blending ratio of ∼0.2. Two existing chemical kinetic models for CH4/CH3Cl mixtures are examined against the measurements, and a modified chloromethane–Polimi–kin model incorporating the Aramco 2.0 model is proposed and validated through comparison with these new data. Based on the proposed model, sensitivity analysis, peak concentration analysis, and reaction pathway analysis are carried out to provide further insight into the ignition process of CH4/CH3Cl/O2/Ar mixtures.

We investigate the role of NO 2 in dimethyl ether (DME) ignition with a combustion shock tube. Ignition delay times are measured at 987−1517 K and 4 and 10 atm. Different equivalence ratios (0.5, 1.0, and 2.0) and NO 2 and DME concentrations are explored. NO 2 promotes DME ignition, and the promoting effect becomes more pronounced at high NO 2 concentrations or low temperatures. NO 2 addition also augments the influence of the equivalence ratio on ignition delay times. Four detailed reaction mechanisms from the literature are examined against the measurements, and an updated kinetic model is proposed and validated in comparison to experiments. On the basis of the updated model, sensitivity analysis, reaction flux analysis, and rate of production analysis are conducted to provide details on the kinetic effect of NO 2 on DME ignition.

Ignition delay times of CH3NHCH3/O2/Ar mixtures are measured with a shock tube in the temperature range of 1040–1604 K. Different pressures (4, 8, and 18 atm) and equivalence ratios (0.5, 1, and 2) are investigated. A recently developed CH3NHCH3 kinetic model is examined, and then modified by adding the hydrogen abstractions from CH3NHCH3 by HO2 and NO2. The rate constants of the hydrogen abstraction by HO2 are estimated by analogy to the CH3OH + HO2 system, and those of the hydrogen abstraction by NO2 by analogy to the CH3NH2 + HO2 system. The modified model is well validated against the present measurements. Based on this model, sensitivity analysis and reaction pathway analysis are performed to provide insight into the chemical kinetics of CH3NHCH3 ignition. CH3NHCH3 is mainly consumed by hydrogen abstractions at low temperatures, and its unimolecular decomposition becomes important at higher temperatures.