Optimizing the Vane-Endwall Junction to Reduce Adiabatic Wall Temperatures in a Turbine Vane Passage

Secondary flows in airfoil passages have become increasingly important in the design of modern gas turbines due to several fundamental trends in gas turbine engine development. Driven to achieve higher engine efficiencies and specific thrust output, the gas turbine industry is continually pushing the envelope of maximum allowable turbine inlet temperature. While many researchers have worked to gain an understanding of secondary flows and their effects on turbine heat transfer, very few have pursued ways to passively mitigate their detrimental effects. While considerable attention has been given to techniques of secondary flow reduction in order to minimize the associated aerodynamic losses, the objective of this study was to improve the thermal environment for a turbine vane. In particular, this objective was achieved through optimizing a fillet in the vaneendwall juncture to minimize adiabatic wall temperatures. The approach taken was to employ a commercial optimization software package in conjunction with a computational fluid dynamics (CFD) package in the design of the fillet. Results indicate that a significant reduction in adiabatic wall temperatures can be achieved through application of an optimized fillet.