Ignition delay times of very-low-vapor-pressure biodiesel surrogates behind reflected shock waves

Ignition delay times for a variety of low-vapor-pressure biodiesel surrogates were measured behind reflected shock waves, using an aerosol shock tube. These fuels included methyl decanoate (C11H22O2), methyl laurate (C13H26O2), methyl myristate (C15H30O2), methyl palmitate (C17H34O2), and a methyl oleate (C19H36O2)/Fatty Acid Methyl Ester (FAME) blend. Experiments were conducted in 4% oxygen/argon mixtures with the exception of methyl decanoate which was studied in 1% and 21% oxygen/argon blends. Reflected shock conditions covered initial temperatures from 1026 to 1388 K, pressures of 3.5 and 7.0 atm, and equivalence ratios from 0.3 to 1.4. Arrhenius expressions describing the experimental ignition delay time data are given and compared to those derived from applicable mechanisms available in the literature. Graphical comparisons between experimental data and mechanism predictions are also provided. Experiments of methyl laurate, methyl myristate, and methyl palmitate represent the first shock tube ignition delay time measurements for these fuels. Finally, experiments with methyl palmitate represent, to the authors’ knowledge, the first neat fuel/oxidizer/diluent gas-phase shock tube experiments involving a fuel which is a waxy solid at room temperature.