Suction Side Film Cooling Measurements in a Linear High-Temperature Cascade at Near-Engine Conditions

Film-cooled turbine blades in a Linear High-Temperature Cascade are investigated experimentally and numerically at a Reynolds number of 120000, low inlet Mach numbers (Ma = 0.2), and main flow temperatures of up to 1050K. Variations in cooling air temperature are used to achieve different density ratios. In addition, the cooling air mass flow is varied for different coolant mass flow ratios. The blades are derived from the mid-section of a high-pressure turbine blade and feature a single row of film cooling holes on the suction side. They are equipped with 66 thermocouples and 37 pressure taps. Film cooling reduces the material temperature in the region downstream of the holes up to 65% of the chord length. High mass ratios of MR > 1.0% result in a reversal of the cooling effect due to the detachment of the cooling film. In summary, we provide temperature and pressure measurements of a film-cooled turbine blade at realistic density and mass flow ratios utilizing a unique linear cascade supplied with high-temperature exhaust gas flow. Our paper contributes to the validation of numerical codes used for the thermal design of turbine blades.