Numerische Modellierung turbulenter Strömung mit Wärmeübergang in einer konvektiv gekühlten Turbinenschaufel

In this thesis, the influence of high order Reynolds stress models and high order models representing the turbulent heat fluxes on the heat flux and the temperature rise in simplified cooling channel geometries as well as on the temperature of a real convective cooled gas turbine blade is analysed. Therefore, numerical results from CFD and CHT calculations are compared to experimental results of the institute`s cooling channel and the hot gas cacade test rig. The aim is to improve the prediction of the inner heat transfer in cooling channels and the temperature distribution of convective cooled gas turbine blades. The results of a smooth and a ribbed configuration of the cooling channel test rig show that the use of high order models for the Reynolds stresses as well as for the turbulent heat fluxes delivers much better results of the inner heat transfer prediction. Though it is important to consider that at first a suitable model for the Reynolds stresses needs to be chosen to represent the flow field as good as possible, before high order models for the turbulent heat fluxes are used. In both configurations the combination of an explicit anisotropic Reynolds stress model with an implemented explicit algebraic model for the turbulent heat fluxes provides the best results. In the convective cooled gas turbine blade the use of an explicit algebraic Reynolds stress model in combination with an explicit algebraic closure of the energy conservation equation not only results in a parallel shift of the temperature level but also in a better prediction of temperature gradients. For example the gradients between the temperature at the stagnation point and the temperature minima at the suction or pressure side can be predicted with higher precision. In conclusion, the high order models for the Reynolds stresses as well as for the turbulent heat fluxes lead to a much better prediction of the CHT results in this application.