2018 Volume 60 Issue 194 Pages 254-259
A methodology to reproduce international variations in diesel spray ignition is proposed. Through two-dimensional gas chromatography and hydrogen nuclear magnetic resonance spectroscopy, a total of 22 species are defined as palette species to model commercial light oils. A surrogate fuel model is formulated with the palette species in such a way that the surrogate fuel model takes over combustion-related properties such as distillation curve, reactivity and soot propensity from the real fuel. The spray combustion simulation coupled with a reaction model showed that the proposed methodology well reproduces the magnitude relationship in international variations of the spray ignition delay times. Moreover, sensitivities of the spray ignition delay time to elemental uncertainties such as the reactivity of the surrogate fuel model, the distillation curves, etc., are systematically analyzed, and the uncertainty of a simulated ignition event is thus quantified. For relatively low temperature condition of 925 K studied in this paper, the combined uncertainty is estimated to be [-7%, 20%] for RANS while [-9%, 28%] for LES, respectively. The uncertainty budget shows that the reactivity of the surrogate fuel model most affects the simulated spray ignition event.
