FLOW IN TURBINE BLADE PASSAGES

IMPROVEMENT IN THE INTERNAL COOLING OF TURBINE BLADES IS IMPORTANT TO CONTINUATION OF THE TREND TOWARDS HIGHER TURBINE INLET TEMPERATURES THAT CAN PROVIDE PERFORMANCE, SIZE AND DURABILITY ADVANTAGES FOR CURRENT AND FUTURE GAS-TURBINE ENGINES. KNOWLEDGE OF THE DETAILED FLOW STRUCTURE IN INTERNAL PASSAGES OF TURBINE BLADES IS NEEDED TO UNDERSTAND MEASURED HEAT TRANSFER PHENOMENA AND TO VALIDATE COMPUTATIONAL ANALYSIS AND DESIGN METHODS. THE OBJECTIVES OF THE PROPOSED PROGRAM ARE TO OBTAIN MEASUREMENTS, VALIDATE COMPUTATIONAL TECHNIQUES, ASSESS COOLING STRATEGIES AND CONTRIBUTE TO DESIGN PRACTICES ALL RELEVANT TO TURBINE-BLADE PASSAGES. RECENTLY-DEVELOPED, REFRACTIVE-INDEX-MATCHING TECHNIQUES WOULD BE USED TO OBTAIN DETAILED MEASUREMENTS OF MEAN AND FLUCTUATING VELOCITY COMPONENTS IN ROTATING PASSAGES WITH GEOMETRIES AND CONDITIONS REPRESENTATIVE OF THOSE FOUND IN GAS-TURBINES AND THIS IS AN INNOVATIVE APPROACH TO THE PROVISION OF THIS VALUABLE INFORMATION. IN PHASE I, A REFRACTIVE-INDEX-MATCHING EXPERIMENT WOULD BE COMPARED TO HEAT TRANSFER RESULTS PREVIOUSLY OBTAINED IN A SIMPLIFIED BUT RELEVANT ROTATING PASSAGE CONFIGURATION. IN PHASE II, THIS EXPERIMENT WOULD BE EXTENDED TO MORE COMPLEX GEOMETRIES CLOSER TO THOSE OF TURBINE-BLADE PASSAGES. RESULTS WOULD BE OBTAINED TO PROVIDE BENCH-MARK DATA FOR PHASE II CODE VALIDATION. THESE EXPERIMENTAL AND COMPUTATIONAL TECHNIQUES WOULD BE ALSO APPLIED IN PHASE II TO ASSESSMENT OF COOLING STRATEGIES IN PREPARATION FOR INTEGRATION INTO TURBINE-BLADE DESIGN SYSTEMS.