Abstract
Abstract
The conditional moment closure (CMC) method with a single flame structure is applied to a heavy duty direct injection diesel engine. The ignition delay, premixed and diffusion controlled combustion and NOx are reasonably predicted with consistent coupling between turbulence and detailed chemistry without any arbitrary tuning constants. The CMC part returns conditional species mass fractions, which are integrated with beta probability density function calculated from mixture fraction and its variance. NOx chemistry includes prompt, thermal and reburn processes. Measured pressure traces and NOx emissions are well reproduced in wide operating conditions with respect to EGR and injection timing. Soot emissions are predicted by a two equation model for transport of particle number density and soot mass fraction, which is based on the mechanisms of particle nucleation, coagulation, surface growth and oxidation. Further improvement is required against extensive database for the soot prediction part.