Les-based assessment of rotation-sensitized turbulence models for prediction of heat transfer in internal cooling channels of turbine blades

A comprehensive model for the prediction of flows in rotating internal cooling channel application is here presented and assessed. The flow field was modelled by using a rotation-sensitized version of the well known k---f elliptic relaxation model. Flow field features in selected planes are discussed to show the changes in velocity field due to the rotation. The discussion is focused on the increase of turbulence close to the ribbed (trailing) surface when rotation is present. In this case the increase of the wall normal pressure gradient leads to an early reattachment of the large recirculation bubble downstream from the rib and to an anticipated development of the boundary layer. Furthermore, Coriolis force enhances the secondary motion. Both phenomena increase mixing and are expected to also increase heat transfer efficiency of the heated surface. This is confirmed by the results of the temperature field. Comparisons with the available experimental results confirm the quality of the prediction.