A Comparative Study of Multi-zone Combustion Models for HCCI Engines

The multi-zone model has been attracting growing attention as an efficient and accurate numerical model for homogeneous charge compression ignition (HCCI) combustion simulations. In this paper, a comparative study was carried out to clarify the effect of various sub-models on the prediction capability of the multi-zone model. The influences of the distribution of zones, heat transfer from the wall, mass and heat exchange between zones and boundary layer thickness on HCCI combustion and emissions were discussed based on the experimental data. The results indicate dividing the colder region into more zones can improve the emissions prediction, however, more zones in the hotter region has little effect on the predictions. The improved Woschni model significantly improves the prediction of heat transfer. It is also found that mass and heat exchange between zones have great influence on the last results, especially that mass exchange model plays an important role in the prediction of CO emissions. While the effect of boundary layer thickness is only slight.