Comparative study on ignition characteristics of n-propylbenzene, 1,3,5-trimethylbenzene and 1,2,4-trimethylbenzene behind reflected shock waves

Alkyl aromatics comprise a significant portion of real fuels. Among various alkyl aromatics, the C9H12 aromatic fuels including n-propylbenzene and trimethylbenzenes are representative alkyl aromatics, which are widely detected in real fuels, and they are widely employed as surrogate compounds in modeling real fuels. Thus, the combustion kinetic study of C9H12 fuels is necessary and urgent for fuel combustion. In this work, comparative experimental and kinetic modeling study of the high-temperature ignition of three C9H12 fuels is performed. New ignition delay time (IDT) measurements are carried out in a high-pressure shock tube (HPST) for 1,2,4-trimethylbenzene and 1,3,5-trimethylbenzene. The studied pressure is 2, 5 and 10 bar, the equivalence ratios are 0.5, 1.0 and 2.0, and the temperature range is from 1090 K to 1600 K for IDT in HPST. The experimental results are simulated using an updated detailed kinetic mechanism. Reaction path analysis and sensitivity analysis are performed to provide insight into the chemical kinetics controlling the ignition of the three C9H12 fuels. The present experimental data set and kinetic model results should be valuable to improve our understanding of the combustion chemistry of alkyl aromatics and to offer practical guidance for the surrogate model development of real fuels.