Aero-Thermodynamic Aspects of Film Cooling in Regions of Separated Flow on the Pressure Side of a High-Lift HPT Blade

Abstract

Due to the ever increasing demand for cost-optimised designs, modern engine design concepts lead to more and more highly loaded HP turbine blades. In order to achieve the high lift required, turbine airfoils will have to cope with main flow diffusion up to separation both on suction and pressure side. Thus, for film cooled HP turbine blades and vanes, the possible aerodynamic and aero-thermal interaction of highly loaded blade rows and film cooling needs to be addressed. The first results to be presented from this ongoing work within the European 5th Frame-Work-Project AITEB jointly comprises experimental high-speed cascade wind-tunnel as well as numerical investigations with state-of-the-art 3D-RANS CFD. Steady and unsteady experimental results detailing the row characteristic of the highly-loaded T120 HP-turbine cascade set the stage for detailed numerical investigations with and without coolant injection from rows of holes on the pressure side surface as well as comparative numerical calculations with different codes and turbulence models. Despite the current focus of the experimental work on aerodynamic topics, the numerical results to be presented comprise thermodynamic investigations and detailed studies on optimised coolant injection geometries as well.