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Heat/Mass Transfer and Friction Characteristic in a Square Duct with Various Discrete Ribs -In-Lined Gap Arrangement Ribs-
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 Title & Authors
Heat/Mass Transfer and Friction Characteristic in a Square Duct with Various Discrete Ribs -In-Lined Gap Arrangement Ribs-
Lee, Se-Yeong; Choe, Cheong; Lee, Dong-Ho; Jo, Hyeong-Hui;
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The present study investigates the effects of various rib arrangements on heat/mass transfer in the cooling passage of gas turbine blades. A complex flow structure occurs in the cooling passage with rib turbulators which promote heat transfer on the wall. It is important to increase not only the heat transfer rates but also the uniformity of heat transfer in the cooling passage. A numerical computation is performed using a commercial code to calculate the flow structures and experiments are conducted to measure heat/mass transfer coefficients using a naphthalene sublimation technique. A square channel (50 mm 50 mm) with rectangular ribs (4 mm 5 mm) is used fur the stationary duct test. The experiments focus on the effects of rib arrangements and gap positions in the discrete ribs on the heat/mass transfer on the duct wall. The rib angle of attack is 60°and the rib-to-rib pitch is 32 mm, that is 8 times of the rib height. With the inclined rib angle of attack (60°), the parallel rib arrangements make a pair of counter rotating secondary flows in the cross section, but the cross rib arrangements make a single large secondary flow including a small secondary vortex. These secondary flow patterns affect significantly the heat/mass transfer on the ribbed wall. The heat/mass transfer in the parallel arrangements is 1.5 ∼2 times higher than that in the cross arrangements. However, the shifted rib arrangements change little the heat/mass transfer from the inline rib arrangements. The gap position in the discrete rib affects significantly the heat/mass transfer because a strong flow acceleration occurs locally through the gap.
Turbine Internal Passage;Discrete Rib;Duct Flow;Heat/Mass Transfer;Pressure Drop;
 Cited by
회전하는 터빈 블레이드 내부 이차냉각유로에서 엇갈린요철과 평행요철이 열/물질전달에 미치는 영향,이세영;이동호;조형희;

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