Heat/Mass Transfer in Smooth and Ribbed Rectangular Serpentine Passages of Different Aspect Ratio's and Orientation

by Agarwal, Peeyush

An experimental study of heat/mass transfer in rectangular smooth and ribbed serpentine passages with and without rotation in two different aspect ratios (1:4 and 4:1) channel is performed for two different orientations of the test section (90-degree and 45-degree). The Reynolds number is varied in the range of 5,000 to 40,000 and rotation numbers in the range of 0-0.12. Such passages are encountered close to the mid-chord sections or towards the trailing edge of the turbine blade. Two different configurations of the Normal ribs (e/Dh=0.3125, P/e=8 and e/Dh=0.156, P/e=11.2) are placed on the leading and the trailing sides. The experiments are conducted in a rotating two-pass coolant channel facility using the naphthalene sublimation technique. For purposes of comparison, selected measurements are also performed in a 1:1 cross-section. The local mass-transfer data in the fully developed region is averaged to study the effect of the Reynolds and the Rotation numbers. The span-wise mass transfer distributions in the smooth and the ribbed cases are also examined.