Numerical Analysis of Internal Cooling Configurations for High-Pressure turbine Blades

Gas turbines represent nowadays one of the most important sources of energy, covering a big slice of the energy need finding a good compromise between energy production and efficiency. Generally, as the system is conceived, to find the aforesaid compromise high temperatures needs to be reached. Thus, cooling mechanisms are adopted by spilling a percentage of the compressor mass-flow rate to refrigerate the areas mostly subjected to this high thermal stresses. Therefore, cooling phenomena represent one of the main subjects to be studied and elaborate in-depth avoiding or at least containing thermo-mechanical stress leading to fatigue cracks. The present thesis aims at investigating and increasing cooling effectiveness within an industrial gas turbine high-pressure blade by means of turbulators. The analysis took advantage of various articles about experimental procedure carried on in channels with this geometry variation, leading to heat transfer enhancement. It is worth saying that pressure losses are added to the system which in turn needs to be faced by increasing the pumping power and so to an efficiency reduction in its global meaning. Firstly, a Matlab® model has been developed implementing correlation trying to find an optimal configuration in terms of heat transfer enhancement and mass-flow rate reduction with respect to a geometry without ribs. Three different rib-turbulators configurations have been tested, each of them with the relative experimental correlation. The work continued performing a model validation by means of Computational Fluid Dynamics thanks to the StarCCM+ solver. Finally, the geometries which resulted to be validated were compared in terms of fluid-dynamic and thermal performances.