Auto-ignition characteristics of a near-term light surrogate fuel for marine diesel: An experimental and modeling study

Abstract

Autoignition characteristics of a four-component surrogate fuel(M2) were investigated in a heated rapid compression machine over a wide range of conditions. The near-term light surrogate M2 developed for marine diesel fuel was formulated in our previous study containing 17.3% n-hexadecane, 5.93% 2,2,4,4,6,8,8-heptamethylnonane, 30% decalin and 46.77% 1-methylnaphthalene by mole fraction. Ignition delay times (IDTs) of gas-phase M2/N2/O2 mixture were measured at pressures of 7, 10, 15 and 20 bar over the temperature range from 675 K to 914 K for the equivalence ratios (ER) of 0.5, 1 and 1.5. NTC behaviours within the temperature of 730–850 K and two-stage ignition phenomena were observed. The effects of operating conditions such as pressure, equivalence ratio and oxygen content were systematically studied, and correlations of total IDTs and first-stage IDTs were performed to further quantitatively reveal the IDTs dependence on the above parameters. Reasonable modifications were made to a literature mechanism to improve its predicting quality. The simulation results using the modified model could satisfactorily reproduce the IDTs under the test conditions, and the model is also able to capture the ignition delay dependence on pressure and fuel/oxygen content. A brute force sensitivity analysis at the low temperature (680 K) and the NTC temperature (780 K) was carried out to identify the key reactions that govern the ignition event of surrogate M2.