TS-81 Heat Transfer Distribution and Flow Behavior in a Rectangular Rib-Roughened Passage for the Parallel and Staggered Rib Arrangements(Session C-10 Turbine Cooling 2)

概要

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Experimentation was conducted to examine the heat transfer and pressure drop characteristics in a rib-roughened rectangular passage with aspect ratio 2:1 for eight rib configurations: 90°, 75°, 60°, 45° parallel and staggered ribs. The ribs were attached to two opposing long side walls (right and left walls) instead of short side walls (top and bottom walls). In this study the oblique ribs were intended to function as secondary flow inducers to improve the heat transfer of the bottom wall (one of the short side walls). The results revealed that, in order to enhance the heat transfer of the bottom wall, the oblique ribs should be arranged so that the flow along the ribs hits the top wall instead of the bottom wall. Flow visualization test was performed to understand the heat transfer mechanisms. It was confirmed that the heat transfer enhancement at the bottom wall was attributed to the ribinduced secondary flow where the flow along the ribs hit the top wall, turned back and carried cold air from the passage core region toward the bottom wall. Due to the stronger rotational momentum of the secondary flow, the average heat transfer is higher for the parallel rib patterns than for the staggered rib patterns. The small heat transfer superiority in the case of parallel rib patterns causes a strong increase of pressure drop in comparison to the staggered rib patterns.
社団法人日本ガスタービン学会の論文
1999-11-14