A shock tube study of the autoignition characteristics of RP-3 jet fuel

Autoignition delay time measurements were performed for gas-phase RP-3/air mixtures behind reflected shock waves at temperatures of 650-1500 K, pressures of 1-20 atm, and equivalence ratios of 0.2, 1.0, and 2.0. Ignition delay times were determined using electronically excited CH∗ and/or OH∗ emissions and reflected shock pressure monitored through the shock tube sidewall. The dependence of the ignition delay times upon temperature, pressure and equivalence ratio has been investigated at high temperatures. Correlation expressions for the ignition delay under different equivalence ratios and pressures have been deduced separately. The global activation energy for RP-3/air varies significantly as the ignition pressure changes. A negative temperature coefficient (NTC) effect for RP-3 at 10 atm was observed in the temperature range of 750-850 K. Current results were compared with available Jet-A ignition data, showing good agreement with previous results of Jet-A. Based on the composition identification of RP-3, a mixture of 88.7% n-decane and 11.3% 1,2,4-trimethylbenzene by mole has been proposed as a surrogate for RP-3. Surrogate mechanism simulations were performed by using the mechanism proposed by Peters et al. (2009). The simulations show good agreement with the experimental data over wide ignition conditions. Sensitivity analyses were carried out to identify the important reactions in the ignition process and to explain the experimental phenomena. Current work provides a fundamental database for the development and validation of surrogate kinetic models for RP-3 jet fuel.