Measured Endwall Flow and Passage Heat Transfer in a Linear Blade Passage With Endwall and Leading Edge Modifications

Abstract

The role of contouring via leading edge fillets or 3-dimensional end wall contouring is examined and compared. The contour endwall profile varies along both the pitch-direction and the axial direction and represents full-passage contouring. The fillets are employed at the corner of blade leading edge and endwall and extend about one-third of the blade axial chord along the blade. Both the endwall contouring and leading edge fillet are employed at the passage bottom endwall. Measurements are obtained for static pressure, pitchwise velocity, flow yaw angle, streamwise vorticity, and Nusselt number on the endwall. The Reynolds number based on the axial chord and passage inlet velocity for the measurements is 2.39×105. The blade surface static pressure coefficients near the endwall indicate no effects of the leading fillet on the blade surface. However, the static pressure difference from the blade-pressure to the blade-suction surface near the endwall shows that the pressure differences generally decrease with the contour endwall and leading edge fillet. This results in less turning of the endwall region flow from the pressure side to suction side in the passage as indicated by reductions in the flow yaw angles and pitchwise velocity with the structural modifications. The streamwise vorticity of the passage vortex is also affected indicating weaker secondary flows in the endwall region for the contour endwall and leading edge fillet cases. The endwall Nusselt numbers are smaller especially upstream of the throat region for the contour endwall and fillet cases.