Advanced near-wall heat transfer modeling for in-cylinder flows

Most of the existing wall heat transfer models employed for in-cylinder flow simulations are not capable of predicting the history and peak value of the heat flux. More comprehensive models that account for density and property variations rely mainly on the standard or low-Reynolds number variants of k-ε turbulence model. Presently applied mesh resolutions already allow for first near-wall computational cells reaching the buffer or locally even viscous/conductive sublayer, thus increasing importance of more sophisticated modeling of near-wall transport phenomena. The present approach relies on the k-ζ-f turbulence model which is capable of capturing turbulent stress anisotropy near wall and predicting heat transfer with more fidelity. A compressible wall function of Han and Reitz is formulated in the framework of hybrid wall treatment. The model is validated against spark ignition (SI) engine heat transfer measurements. Predicted wall heat flux evolutions on the cylinder head exhibit very good agreement with the experimental data, being superior to similar numerical predictions available in the published literature.