Pressure drop and mass transfer in two-pass ribbed channels

The combined effects of the sharp 180-deg turn and of the rib configuration on the pressure drop and mass transfer characteristics in a two-pass square channel with a pair of opposite rib-roughened walls (to simulate turbine airfoil cooling passages) were determined for a Reynolds number range of 10,000-60,000. For pressure drop experiments, the rib height-to-hydraulic diameter ratios e/D were 0.063 and 0.094; the rib pitch-to-height ratios P/e were 10 and 20; the rib angles-of-attack a were 90, 60, and 45 deg. For mass transfer experiments, the top, bottom, inner, and outer walls of the test channel were naphthalene-coated surfaces; the e/D ratio was 0.063; the P/e ratio was 10; the a was 90 or 60 deg. Heat transfer enhancements were compared for the first pass and for the two-pass channel with the sharp 180-deg turn. Correlations for the fully-developed friction factors and loss coefficients were obtained. American Institute of Aeronautics and Astronautics, Inc., 1989, All rights reserved.

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