Full Scale Turbine Vane Endwall Film Cooling Effectiveness Distribution Using Pressure Sensitive Paint Technique

Abstract

Researchers in gas turbine field take great interest in the cooling performance on the firststage vane because of the complex flow characteristics and intensive heat load that comes from the exit of the combustion chamber. A better understanding is needed on how the coolant flow interacts with the mainstream and the resulting cooling effect in the real engine especially for the firststage vane. An authentic flow channel and condition should be achieved. In this study, three fullscale turbine vanes are used to construct an annularsector cascade. The filmcooling design is attained through numerous layback fanshaped and cylindrical holes dispersed on the vane and both endwalls. With the threedimensional vane geometry and corresponding wind tunnel design, the true flow field can thus be simulated as in the engine. This study targets the filmcooling effectiveness on the inner endwall (hub) of turbine vane. Tests are performed under the mainstream Reynolds number 350,000; the related inlet Mach number is 0.09; and the freestream turbulence intensity is 8%. Two variables, coolanttomainstream mass flow ratios (MFR = 2%, 3%, and 4%) and density ratios (DR = 1.0 and 1.5), are examined. Pressuresensitive paint (PSP) technique is utilized to capture the detail contour of filmcooling effectiveness on the inner endwall and demonstrate the coolant trace. The presented results serve as a comparison basis for other sets of vanes with different cooling designs. The results are expected to strengthen the promise of PSP technique on evaluating the filmcooling performance of the engine geometries.