Autoignition of n-Decane/n-Butylbenzene/n-Propylcyclohexane Mixtures and the Effects of the Exhaust Gas Recirculation

In the present work, the autoignition of single-component and binary mixtures composed of n-decane, n-butylbenzene, and/or n-propylcyclohexane has been investigated using shock-tube techniques. In addition, the effects of the presence of the exhaust gas recirculation (EGR) components on the autoignition behavior of a 4:3:3 molar n-decane: n-butylbenzene:n-propylcyclohexane surrogate mixture have been investigated experimentally. The experiments have been performed at highly diluted conditions in argon bath gas, over a wide range of temperatures (1250-1750 K), equivalence ratios (phi = 0.2-1.5), and nominal pressures of 10-20 bar. A chemical kinetic model was developed to simulate the newly obtained experimental data by blending sub-models from the literature. In particular, the experimental and numerical analyses suggest that the observed increase in the ignition delay times in the presence of EGR is mainly due to the dilution levels and not to the chemistry of the fuel. Additional kinetic analyses were performed to compare the high-temperature autoignition properties of the different components considered herein.