Heat transfer in hcci phenomenological simulation models: A review

Abstract

This study presents a review of the heat transfer treatment in HCCI phenomenological simulation models, including single-zone and multi-zone ones. Heat transfer within the combustion chamber is significant when modeling the internal combustion engine in general and the HCCI combustion process in particular. It determines to a great extent the temperature field within the combustion chamber throughout the engine operating cycle, and especially during compression and combustion. In HCCI engines, combustion relies upon the auto-ignition of a premixed charge that is present for most—if not all—of the compression stroke. In this combustion mode the heat transfer process directly affects mean gas and local temperatures, thereby influencing ignition timing, combustion rate and the formation of HC, CO and NOx emissions. The success of any simulation model in describing or predicting the HCCI combustion process and emissions formation evidently depends partly on its ability to reliably predict the heat transfer phenomena involved.Despite the importance of the heat transfer process in HCCI simulation, little progress has been made in the past years, compared to the advances that have been achieved experimentally. Moreover, the information regarding phenomenological heat transfer treatment is scattered. The aforementioned provided the motivation for this review that provides initially a critical outlook on the heat transfer correlations that were derived for conventional combustion modes, since these correlations have been—and are still—used frequently in HCCI simulation models. The underlying assumptions of these correlations and the conditions under which they were validated are explicitly stated, in order to appraise their suitability in HCCI phenomenological simulations. Heat transfer treatment in single-zone and multi-zone models is presented subsequently, including HCCI-specific correlations that have been developed in the past years. Issues such as zone configuration, wall heat transfer correlations based on global or local gas properties, and inter-zonal heat transfer are discussed. Moreover, comparative studies that evaluate the relative effectiveness of different correlations are presented. The study concludes with general remarks on phenomenological heat transfer simulation and with suggestions for further research.