Computations of Flow Structures and Heat Transfer in a Dimpled Channel at Low to Moderate Reynolds Number

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dc.contributor.authorPatrick, Wilfred Vinoden
dc.contributor.committeechairTafti, Danesh K.en
dc.contributor.committeememberRagab, Saad A.en
dc.contributor.committeememberVick, Brian L.en
dc.contributor.departmentMechanical Engineeringen
dc.date.accessioned2014-03-14T20:39:20Zen
dc.date.adate2005-08-23en
dc.date.available2014-03-14T20:39:20Zen
dc.date.issued2005-04-25en
dc.date.rdate2005-08-23en
dc.date.sdate2005-06-04en
dc.description.abstractTime-accurate calculations are used to investigate the three-dimensional flow structure and understand its influence on the heat transfer in a channel with concave indentations on one wall. A dimple depth to channel height ratio of 0.4 and dimple depth to imprint diameter ratio of 0.2 is used in the calculations. The Reynolds number (based on channel height) varies from Re = 25 in the laminar regime to Re = 2000 in the early turbulent regime. Fully developed flow and heat transfer conditions were assumed and a constant heat flux boundary condition was applied to the walls of the channel. In the laminar regime, the flow and heat transfer characteristics are dominated by the recirculation zones in the dimple with resulting augmentation ratios below unity. Flow transition is found to occur between Re = 1020 and 1130 after which both heat transfer and friction augmentation increase to values of 3.22 and 2.75, respectively, at Re = 2000. The presence of large scale vortical structures ejected from the dimple cavity dominate all aspects of the flow and heat transfer, not only on the dimpled surface but also on the smooth wall. In all cases the thermal efficiency using dimples was found to be significantly larger than other heat transfer augmentation techniques currently employed.en
dc.description.degreeMaster of Scienceen
dc.identifier.otheretd-06042005-145209en
dc.identifier.sourceurlhttp://scholar.lib.vt.edu/theses/available/etd-06042005-145209/en
dc.identifier.urihttp://hdl.handle.net/10919/33415en
dc.publisherVirginia Techen
dc.relation.haspartetd_thesis.pdfen
dc.rightsIn Copyrighten
dc.rights.urihttp://rightsstatements.org/vocab/InC/1.0/en
dc.subjectFlow structureen
dc.subjectTransitionen
dc.subjectDNSen
dc.subjectConcavitiesen
dc.subjectDimplesen
dc.titleComputations of Flow Structures and Heat Transfer in a Dimpled Channel at Low to Moderate Reynolds Numberen
dc.typeThesisen
thesis.degree.disciplineMechanical Engineeringen
thesis.degree.grantorVirginia Polytechnic Institute and State Universityen
thesis.degree.levelmastersen
thesis.degree.nameMaster of Scienceen

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