Future engine requirements, including high-altitude flight of unmanned air vehicles, as well as an impetus to reduce engine cost and weight, are challenging the current state of the art in low-pressure-turbine airfoil design. These new requirements present low-Reynolds number challenges as well as the need for high-performance, high-lift design concepts. Here we report on an effort to expand the relatively well established aerodynamic design space for low-pressure turbine airfoils through the application of recent developments in transition modeling to airfoil design. Analytical and experimental mid-span performance data and predicted loadings are presented for four high-lift airfoil designs based on the Pack B velocity triangles. The new designs represent a systematic expansion of low-pressure turbine airfoil design space through the application of high-lift design concepts for front- and aft-loaded airfoils. All four designs performed as predicted across a range of operationally representative Reynolds numbers. Full-span loss data for the new high-lift designs reveal increased endwall losses, which, with the application of non-axisymmetric endwall contouring, have been substantially reduced. Taken holistically, the results presented here demonstrate that accurate transition modeling provides a reliable method to develop optimized, very high-lift airfoil designs. However, further improvements in endwall-loss mitigation technologies are required to enable the implementation of the very high-lift technology presented here in engine systems.
Toward the Expansion of Low-Pressure-Turbine Airfoil Design Space
Praisner, TJ, Grover, EA, Knezevici, DC, Popovic, I, Sjolander, SA, Clark, JP, & Sondergaard, R. "Toward the Expansion of Low-Pressure-Turbine Airfoil Design Space." Proceedings of the ASME Turbo Expo 2008: Power for Land, Sea, and Air. Volume 6: Turbomachinery, Parts A, B, and C. Berlin, Germany. June 9–13, 2008. pp. 1323-1331. ASME. https://doi.org/10.1115/GT2008-50898
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