CFD Study of Heat Transfer in a Spark-Ignition Engine Combustion Chamber

The objective of this study is the thermal investigation of a typical spark-ignition (SI) engine combustion chamber with particular focus in determination of the locations where the heat flux and heat transfer coefficient are highest. This subject is an important key for some design purposes especially thermal loading of the piston and cylinder head. To this end, CFD simulation using the KIVA-3V CFD code on a PC platform for flow, combustion, and heat transfer in a typical SI engine has been performed. Some results including the temporal variation of the area-averaged heat flux and heat transfer coefficient on the piston, combustion chamber, and cylinder wall are presented. Moreover, the temporal variation of the local heat transfer coefficient and heat flux along a centerline on the piston as well as a few locations on the combustion chamber wall are shown. The investigation reveals that during the combustion period, the heat flux and heat transfer coefficient vary substantially in space and time due to the transient nature of the flame propagation. For example, during the early stages of the flame impingement on the wall, the heat flux undergoes a rapid increase by as much as around 10 times the preimpingement level. In other words, the initial rise of the heat flux at any location is related to the time of the flame arrival at that location.