This paper presents a new approach for assessing rotor blade cooling concepts. A new test rig has been designed, built and commissioned, allowing fast comparison of different cooling schemes as well as absolute surface temperature measurements for different cooling concepts. By scaling the test specimen, full aerothermal similarity was achieved at high measurement accuracy and resolution. This similarity however poses high demand on the employed measurement techniques.
Surface temperature (and thus cooling effectiveness) is measured using high resolution, high dynamic range infrared thermography with an improved calibration method for in-situ radiation correction. Furthermore, an improved image evaluation algorithm is presented, allowing angle-of-view dependent emissivity correction and full 3D-evaluation of image data. Those improvements enable the measurement on strongly cooled and strongly curved surfaces, and thus the use of scaled rotor blades with true geometry. First results are presented comparing total cooling effectiveness of a conventionally cooled blade with internal ribs to the effectiveness of an internal swirl design blade. They show the feasibility of the measurements and the importance of the presented correction method.
