A Shock Tube Study of the Ignition of n-Heptane, n-Decane, n-Dodecane, and n-Tetradecane at Elevated Pressures

Abstract

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 C7 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.