Eddy-Resolving Simulation of Conjugate Heat Transfer in a Test Specimen pertinent to Cooling Channels in IC Engines 2024-01-2692

The conjugate heat transfer, which effectively integrates the heat conduction within the solid metal block of the so-called Water Spider Geometry (WSG) configuration and the fluid domain within it, is computationally investigated in the present work, allowing an accurate representation of the temperature conditions at the solid-fluid interface. The WSG configuration represents a specially configured tube geometry that effectively reproduces the flow behavior observed in cooling channels associated with Internal Combustion (IC) engines. The inherent high flow unsteadiness potential of the WSG flow configuration, resulting from the complex flow guidance involving phenomena such as flow impingement, bifurcation, multiple deflections and flow confluence, requires the application of a model capable of capturing turbulence fluctuations. Consequently, the solutions for the coupled flow and thermal fields are obtained by applying a novel eddy-resolving method employing the sub-scale model for solving the equations governing the unresolved residual turbulence quantities. For the latter, a four-equation model is used that solves, in addition to the equations governing the subscale kinetic energy of turbulence and its dissipation rate, the equation describing the dynamics of the normal-to-wall turbulence intensity component. The results obtained for two distinct fluid flow rates and a heat transfer rate, corresponding closely to those encountered in IC-related cooling channels, are discussed along with the reference flow data obtained with high-resolution LES and scale-resolved Sensitized RANS methods and the experimentally determined wall temperatures.