Ignition Delay Measurements of a Methylcyclohexane/O_2/Ar Mixture over a Wide Range of Conditions

摘要

Cycloparaffins may constitute 20% or more by volume of jet fuels. Methylcyclohexane (MCH) is commonly used as a surrogate to represent the monocycloparaffin fraction in jet fuels. In this study, gas phase ignition delay times for a MCH/O2/Ar mixture were measured using a single pulse reflected shock tube at the University of Dayton Research Institute (UDRI). In this study, ignition delay measurements covered a pre-ignition temperature of 975-1800 K, at pre-ignition pressures of 2 and 20 atm, at equivalence ratios of 0.5 and 1, and argon concentrations of 93% and 98%. Ignition delay were measured using the end wall pressure and the white light, OH~*, CH~* chemiluminescence emissions. In addition, experimental data were compared with modeled data using the detail chemical kinetics mechanism for MCH combustion developed by Pitz at al. It was observed that the equivalence ratio affects the ignition delay time. For the lower argon concentration (Ar = 93%) and higher pressure (P = 20 atm), at lower temperatures (T<～1150 K) ignition delay times were shorter for rich conditions when compared to leaner conditions. An opposite trend was observed at the higher temperatures (T>～1150 K). In addition, longer ignition delay times were observed at the lower pressure (P = 2 atm), and higher argon concentration (Ar = 98%).