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dc.contributor.authorMartorell, Ingrid
dc.contributor.authorHerrero, Joan
dc.contributor.authorGrau, Francesc X.
dc.date.accessioned2016-06-23T09:43:43Z
dc.date.issued2003
dc.identifier.issn0017-9310
dc.identifier.urihttp://hdl.handle.net/10459.1/57279
dc.description.abstractThe present work deals with the natural convection flow and heat transfer from a horizontal plate cooled from above.Experiments are carried out for rectangular plates having aspect ratios between / ¼ 0:036 and 0.43 and Rayleigh numbers in the range 2906Raw 63:3 105.These values of Raw and / have been selected below those commonly considered in previous research in view of a future application to the design of printed circuit boards.The plates are made of two different metals, copper and steel.The choice of a metal is relevant to the present problem because the plates are heated by means of an electric current.Important variations of the surface temperature are observed along the transverse direction for the steel plates.The surface of the copper plates is almost isothermal because of the high thermal conductivity of the metal. Calculations for a semi-infinite plate are carried out to predict the transverse profiles of the surface temperature and heat flux and to visualize the structure of the flow.Three-dimensional calculations are also used at a qualitative level to observe the changes in the flow structure due to the finite length of the plate.Present results are compared with both previous experimental work and analyses that are based on boundary layer theory.It is shown that analyses for an infinite boundary layer are not completely applicable to the present problem because of its different physics.The most relevant feature of the natural convection flow, which is not predicted by boundary layer analyses, is a thermal plume rising near the center of the plate. Present heat transfer results differ from previous experimental work because of the lower Rayleigh numbers and aspect ratios investigated here.The Nusselt number is found to depend on Ran w, with the exponent n ¼ 0:17 being lower than most of the values reported in the literature.This comparatively low value is related to the transverse conduction of heat through the air, which becomes increasingly significant as Raw approaches zero.It is shown that such a low-Raw effect can be accounted for in a physically consistent manner by adding a constant term to the heat transfer correlation. On the other hand, it is found that the Nusselt number does not significantly depend on the aspect ratio in the range of / investigated contrary to what has been previously reported for wider plates.ca_ES
dc.description.sponsorshipThe present research has been mainly supported by the Spanish Government through the projects DGESPB96- 1011, DGESYIC-PPQ-2000-1339, and DGESYIC- DPI2000-1578-C02-01.Additional support has been received from the Catalan Government through projects 1998-SGR-00102, 1999-SGR-00338 and 2000- SGR-00103.These sources of funding are gratefully acknowledged.ca_ES
dc.language.isoengca_ES
dc.publisherElsevierca_ES
dc.relation.isformatofReproducció del document publicat a https://doi.org/10.1016/S0017-9310(03)00010-3ca_ES
dc.relation.ispartofInternational Journal of Heat and Mass Transfer, 2003, vol. 46, p. 2389-2409ca_ES
dc.rights(c) Elsevier, 2003ca_ES
dc.subjectHeat transferca_ES
dc.subjectNatural convectionca_ES
dc.subjectPlateca_ES
dc.titleNatural convection from narrow horizontal plates at moderate Rayleigh numbersca_ES
dc.typearticleca_ES
dc.identifier.idgrec007301
dc.type.versionpublishedVersionca_ES
dc.rights.accessRightsinfo:eu-repo/semantics/restrictedAccessca_ES
dc.identifier.doihttps://doi.org/10.1016/S0017-9310(03)00010-3
dc.date.embargoEndDate10000-01-01


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