Date of Award
Master of Science in Aeronautical Engineering
Department of Aeronautics and Astronautics
Marc D. Polanka, PhD
Recent experiments have attempted to quantify the overall cooling effectiveness at elevated temperature conditions. The Film Cooling Rig (FCR) at the Air Force Institute of Technology has been modified to better match the configuration of a similar large scale, low temperature rig at the Air Force Research Laboratory. This has enabled comparison and trend identification of how various properties scale from the low to high temperature condition. Various internal cooling and hole geometry configurations were investigated over a range of temperatures while utilizing the thermal scaling capability of Inconel 718. Film cooling trends and measures of overall effectiveness were matched, indicating the ability to scale among the temperature ranges tested: 350 K, 450 K, 500 K, and 550 K. Effects of blowing ratio, density ratio, and Reynolds number on overall effectiveness were investigated, as well as the ability of scaling effectiveness measurements between temperature regimes. It was found that an increase in Reynolds number caused a decrease in overall effectiveness. When matching flow parameters, this investigation found direct overall effectiveness scaling to be plausible. Additionally, overall effectiveness of about 0.5-0.6 during cases of no coolant flow were experienced due to conductive cooling to the environment. The highly conductive material also created significant heating of the coolant, drastically decreasing density ratio at the area of interest during testing, which plays an important role in assessing cooling performance.
DTIC Accession Number
Lynch, Ryan A., "Investigation of Thermal Scaling Effects for a Turbine Blade Leading Edge and Pressure Side Model" (2016). Theses and Dissertations. 2359.