The computation of flow and heat transfer through square-ended U-bends, using low-Reynolds-number models

Nikas, K-SP; Iacovides, H

dc.contributor.author	Nikas, K-SP	en
dc.contributor.author	Iacovides, H	en
dc.date.accessioned	2014-03-01T01:21:37Z
dc.date.available	2014-03-01T01:21:37Z
dc.date.issued	2004	en
dc.identifier.issn	0961-5539	en
dc.identifier.uri	https://dspace.lib.ntua.gr/xmlui/handle/123456789/16270
dc.relation.uri	http://www.scopus.com/inward/record.url?eid=2-s2.0-1842431051&partnerID=40&md5=a30be18e9e7a5f7866650eaa725ad96f	en
dc.subject	Flow measurement	en
dc.subject	Heat transfer	en
dc.subject	Modelling	en
dc.subject	Turbulent flow	en
dc.subject.classification	Thermodynamics	en
dc.subject.classification	Mathematics, Interdisciplinary Applications	en
dc.subject.classification	Mechanics	en
dc.subject.other	Flow measurement	en
dc.subject.other	Heat flux	en
dc.subject.other	Kinetic energy	en
dc.subject.other	Nusselt number	en
dc.subject.other	Prandtl number	en
dc.subject.other	Reynolds number	en
dc.subject.other	Stress analysis	en
dc.subject.other	Tensors	en
dc.subject.other	Turbulence	en
dc.subject.other	Turbulent flow	en
dc.subject.other	Reynolds stress	en
dc.subject.other	Turbulence modeling	en
dc.subject.other	Heat transfer	en
dc.subject.other	bend	en
dc.subject.other	fluid flow	en
dc.subject.other	heat transfer	en
dc.subject.other	pipe	en
dc.title	The computation of flow and heat transfer through square-ended U-bends, using low-Reynolds-number models	en
heal.type	journalArticle	en
heal.language	English	en
heal.publicationDate	2004	en
heal.abstract	This study is concerned with the computation of turbulent flow and heat transfer in U-bends of strong curvature. Following the earlier studies within the authors' group on flows through round-ended U-bends, here attention is turned to flows through square-ended U-bends. Flows at two Reynolds numbers have been computed, one at 100,000 and the other at 36,000. In the heat transfer analysis, the Prandtl number was either 0.72 (air) or, in a further departure from our earlier studies, 5.9 (water). The turbulence modelling approaches examined, include a two-layer and a low-Re k-ε. model, a two-layer and a low-Re version of the basic differential stress model (DSM) and a more recently developed, realisable version of the differential stress model that is free of wall-parameters. For the low-Re effective viscosity model (EVM) and DSMs, an alternative, recently proposed length-scale correction term, independent of wall distance has also been tested. Even the simplest model employed - two-layer EVM - reproduces the mean flow development with reasonable accuracy, suggesting that the mean flow development is mainly influenced by mean pressure rather than the turbulence field. The heat transfer parameters, on the other hand, show that only the low-Re DSMs produce reliable Nusselt number predictions for both Prandtl numbers examined.	en
heal.publisher	EMERALD GROUP PUBLISHING LIMITED	en
heal.journalName	International Journal of Numerical Methods for Heat and Fluid Flow	en
dc.identifier.isi	ISI:000223932800003	en
dc.identifier.volume	14	en
dc.identifier.issue	3	en
dc.identifier.spage	305	en
dc.identifier.epage	324	en