Abstract
Uncertainty of a simulated ignition event in diesel spray combustion is quantified for both RANS and LES. Sensitivities to elemental uncertainties such as the reaction rates of the surrogate fuel model, the distillation temperature, turbulent Schmidt number, turbulent Prandtl number, fitting of spray break-up models, and Smagorinsky constant in LES are analyzed. For relatively low temperature condition of 925 K, the combined uncertainty of the ignition delay time is estimated to be [-7%, 20%] for RANS while [-9%, 28%] for LES, respectively. The uncertainty budget shows that the reaction rate of progress of the surrogate fuel model most affects the simulated spray ignition event.
