Experimental and kinetic modeling study on ignition characteristic of 0# diesel in a shock tube

Abstract

The understanding of autoignition characteristics of fuels is essential for the design of engines and the optimization of combustion organization. However, the autoignition and chemical kinetics of 0# diesel, a typical diesel fuel designed aimed at Chinese national stage VI emission standard, are seldom investigated. In this paper, ignition delay times (IDTs) for 0# diesel/air were measured using a shock tube over the temperature range of 1041−1307 K, pressures of 2−10 atm, and equivalence ratios of 0.5−1.5. The effects of pressure and equivalence ratio on ignition delay times were systematically analyzed. It was found that the ignition delay times were sensitive to the factor of pressure and less sensitive to the factor of equivalence ratio. In order to clarify the chemical mechanism that govern the ignition process, a kinetic model was further developed to describe the reaction network of 0# diesel. Firstly, a ternary surrogate fuel (30.73% n-hexadecane, 28.31% iso-cetane, and 40.96% propyl-benzene by mole) was proposed for 0# diesel based on the combustion property target matching strategy using an automatically iterated method. The results showed that the proposed surrogate model reproduced the crucial property targets of the real diesel with a deviation of less than 3%, including cetane number (CN), molecular weight (MW), low heat value (LHV) and hydrogen/carbon ratio(H/C). On this basis, a skeletal mechanism was proposed for 0# diesel and validated against the experimental results obtained in the current study. Comparisons between results from simulation and present experimental results showed that the mechanism can accurately describe the autoignition characteristics of 0# diesel. Experimental data and mechanism presented in this study will provide insight into the understanding the combustion progress of 0# diesel and can be used for numerical simulations.