The ignition of n-heptane, n-decane, n-dodecane, and n-tetradecane has been investigated in a heated shock tube. n-Alkane/air mixtures at Φ ) 0.25, 0.5, and 1.0 were studied in reflected shock experiments at 9-58 atm and 786-1396 K. Ignition times were measured using a combination of endwall electronically excited OH emission and sidewall pressure measurements. The measured ignition times are compared to previous data, where available, with good agreement and to several kinetic modeling predictions. The current data and the combination of the current data with previous shock tube and rapid compression machine measurements show that any differences in reactivity for C 7 and larger n-alkanes is slight, within the experimental uncertainties, for n-alkane/air mixtures with common carbon content at a large range of temperatures (650-1400 K) and elevated pressures. To our knowledge, the n-tetradecane measurements presented here are the first ignition measurements to be reported for this compound. The complete data set greatly extends the kinetic modeling targets available for large n-alkanes at elevated-pressure conditions relevant to practical combustion devices.

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The ignition of methylcyclohexane (MCH)/air and ethylcyclohexane (ECH)/air mixtures has been studied in a shock tube at temperatures and pressures ranging from 881 to 1319 K and 10.8 to 69.5 atm, respectively, for equivalence ratios of 0.25, 0.5, and 1.0. Endwall OH* emission and sidewall pressure measurements were used to determine ignition delay times. The influence of temperature, pressure, and equivalence ratio on ignition has been characterized. Negative temperature coefficient behavior was observed for temperatures below 1000 K. These measurements greatly extend the database of kinetic targets for MCH and provide, to our knowledge, the first ignition measurements for ECH. The combination of the MCH measurements with previous shock tube and rapid compression machine measurements provides kinetic targets over a large temperature range, 680-1650 K, for the validation of kinetic mechanisms. C 2008 Wiley Periodicals, Inc. Int J Chem Kinet 41: [82][83][84][85][86][87][88][89][90][91] 2009

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