Airfoil Trailing Edge (TE) cooling is critical for turbine blade and nozzle lifing and safety. Gas turbines overall efficiency enhancement requires further increasing of the turbine inlet temperature and decreasing of cooling flow usage. This requires more advanced TE designs to meet the inherent conflicting requirements. Aerodynamic requirements of thin TE, particularly in jet engines, lead to Pressure Side (PS) cutback of the TE with a span-wise slot forming uniform cooling film over the cutback/floor region.
This study focused on the PS cutback TE film effectiveness and flow field measurements of a standard geometry with t/s=0.9. The measurements were conducted in a subsonic open loop wind tunnel with a generic setup to cover different TE running conditions. IR camera is used to measure the TE coupon surface temperature distribution. The test conditions are characterized by a constant main flow Mach number with constant gas temperature. CO2 at constant temperature is used as the coolant to reach the realistic blowing ratio and density ratio. Inlet boundary layer is measured by the Particle Image Velocimerty (PIV) to characterize the TE flow conditions and study the underlying flow physics. The experimental data for 2D wall contours and laterally-averaged profiles of adiabatic film effectiveness, velocity vector field and boundary layer profiles were discussed. These data will be used to provide inlet boundary conditions and validate CFD simulations in Part 2.