Titre :
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Turbulent heat and fluid flow in a passage disturbed by detached perforated ribs of different heights
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Auteurs :
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T. Liou ;
S. Chen
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Type de document :
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article/chapitre/communication
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Année de publication :
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1998
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ISBN/ISSN/EAN :
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International journal of heat mass transfer, vol 4
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Format :
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p.1795-1806
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Langues:
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= Anglais
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Catégories :
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SCIENCES FONDAMENTALES ET APPLIQUEES
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Mots-clés:
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ECOULEMENT TURBULENT
;
TRANSFERT DE CHALEUR
;
HOLOGRAPHIE
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Résumé :
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The spatially periodic turbulent heat transfer and friction in a rectangular passage of width-to-height ratio of 4:1 with perforated rectangular ribs detached from one wall have been studied using laser holographic interferometry, smoke-streak flow visualization, and pressure probing for rib-to-duct hydraulic diameter ratios (H/De) of 0.081, 0.106, and 0.162 and Reynolds number (Re) range of 5 x 10(3)-5 x 10(4). The rib pitch-to-height ratio and the detached distance-to-rib-height ratio are 10 and 0.38, respectively. The laser-Doppler velocimetry measurements were performed to illustrate the local Nusselt number distribution. In contrast to the attached solid-type ribs which provide a monotonic decrease of thermal performance at a constant pumping power ((p)/(s)*) with increasing rib height, the detached perforated-type ribs give a best (p)/(s)* at a moderate rib height H/De = 0.106 for the lower Re range and a (p)/(s)* independent of H/De for the higher Re range. In addition, the thermal performance of the detached solid-type ribs is found to be superior to that of the detached perforated-type ribs and the physical reason for the difference is addressed.
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