Turbulent heat transfer from a multi-layered wall-mounted cube matrix: a large eddy simulation

The dynamics of flow and heat transfer on internally heated multi-layered matrix of cubes mounted on one of the walls of a plane channel is investigated by numerical simulation using a finite-volume unstructured solver. The fluid flow and convective heat transfer were solved by large eddy simulation (LES). The temperature field in the cube mantle and on its outer surface – providing the boundary conditions for the convection – was obtained by solving the conduction equation simultaneously with the velocity field. The simulations were performed on the parallel CrayT3E computer at TU Delft using about 425.000 cells clustered around the cube surface and the base wall. The standard Smagorinsky subgrid-scale model was used for LES, with Spalartʹs adjustment of the filter width in the near-wall region. Comparisons with experiments and with LES on structured orthogonal meshes reported in the literature show good agreement. The temperature distribution on the cube surface was found to be very nonuniform reflecting complex vortex and turbulence structure around the cube. Numerical flow visualisation and animation are used to provide a better insight into the flow pattern and vortex structure and their relation with the local heat transfer and temperature distribution. The configuration considered is relevant to cooling of electronic components on circuit boards or cooling of gas-turbine blades through internal passages equipped with ribs or pins.