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Accurate predictions of in-cylinder heat transfer processes of internal combustion engines (ICEs) require a comprehensive understanding of the boundary layer development in the near-wall region (NWR). To add to the understanding of this NWR, this study uses experimental data of near-wall measurements collected in the transparent combustion chamber (TCC-III) engine via Particle Image Velocimetry (PIV) and toluene Planar Laser Induced Fluorescence (PLIF) thermometry. These near-wall flow and temperature distributions were compared with large-eddy simulations (LES) and 3-D conjugate heat transfer (CHT) modeling with a commercial CFD code (CONVERGE). The implementation of the conjugate heat transfer model enables capturing the variability in wall heat transfer as observed in the measurements.

A one-dimensional, non-equilibrium, compressible law of the wall model is proposed to increase the accuracy of heat transfer predictions from computational fluid dynamics (CFD) simulations of internal combustion engine flows on engineering grids. Our 1D model solves the transient turbulent Navier-Stokes equations for mass, momentum, energy and turbulence under the thin-layer assumption, using a finite-difference spatial scheme and a high-order implicit time integration method. A new algebraic eddy-viscosity closure, derived from the Han-Reitz equilibrium law of the wall, with enhanced Prandtl number sensitivity and compressibility effects, was developed for optimal performance. Several eddy viscosity sub-models were tested for turbulence closure, including the two-equation k-epsilon and k-omega, which gave insufficient performance.