2017 Volume 59 Issue 189 Pages 200-208
The vehicle emission regulations have been driving forces for advancing the technologies of vehicle engines. Recently, gasoline vehicles, particularly, Gasoline Direct Injection (GDI) vehicles were subjected to regulations of PM (Particulate Matter) emissions in addition to diesel vehicles. In order to develop the engine of lower PM emissions, a computational fluid dynamics (CFD) simulation becomes powerful tool with developing high-performance computers. A PM model is required for CFD to predict PM emissions in an engine cylinder. Particularly, soot particle model is important because the major component of PM is found to be Elemental Carbon (EC). In this article, we review the soot particle calculation by using the method of moment as one of typical way of soot calculations. The nucleation, coagulation and surface reactions of soot particle are explained. The example of the soot calculation is introduced. The PAH growth mechanism for C1–C4 gaseous fuels (KAUST PAH Mechanism 2, KM2) was tested for the recent experimental data of the soot formation of C3H8/air mixture in a shock tube. The mechanism includes molecular growth up to coronene and 36 of nucleation reactions. The effect of nucleation reactions on computed soot generation characteristics was investigated using Chemkin-Pro with the method of moment for soot particle calculations. The calculated results were in good agreement with experimental data. Coronene and 4 ring PAHs were the major soot precursors at high temperature (~2000K) and low/middle temperature range (below 2000K), respectively.
