In-cylinder combustion modeling and validation using Fluent

A key element for thermal stress analysis of engine blocks and cylinder heads is an accurate representation of the temperature distribution in the given component. In order to predict the temperature accurately, spatially resolved thermal boundary conditions from the cylinder are required. For the SI engine studied, the Zimont [1] model is used for the in-cylinder combustion and the heat transfer coefficient is time averaged for subsequent thermal stress analysis. Pressure and burn rate data from Fluent were validated against experiments. The calculated heat transfer coefficients show large spatial variation and thus confirm that the traditional uniform heat transfer coefficient approach would give a far less accurate temperature distribution and therefore a less accurate representation of the actual thermal stress for the engine components.