The numerical computation of turbulent convective heat transfer

This paper discusses computations of convective heat transfer in complex turbulent flows. They include features such as secondary motion, streamline curvature, orthogonal rotation, flow separation, impingement and surface rib-roughness. The computations involve effective viscosity (EVM) models and second-moment closures. Conclusions are drawn on the effectiveness of turbulence modelling approximations. In flow simulations of three-dimensional boundary layers induced by rotation or curvature, the integration of the flow equations across the viscous sub-layer becomes necessary. When streamline curvature is present, the introduction of second-moment closures can further improve flow and thermal computations. Curvature-induced separation is better predicted using near-wall second-moment closures. Low-Reynolds-number second-moment closures are also necessary when rotational buoyancy becomes important. Effective-viscosity models also fail to predict the correct wall heat-transfer in stagnation regions. As also found for flows through curved passages, heat transfer in stagnation regions is better predicted by recently developed realisable second-moment models. Non-linear k-epsilon models performed well in stagnation regions. Low-Re DSM closures have been found to be necessary for heat transfer predictions in ribbed passages. An length scale correction term for low-Re models, independent of the wall distance, is also proposed.