Laminar forced convection heat transfer of a non-newtonian fluid in a square duct
01 Dec 1977-International Journal of Heat and Mass Transfer (Pergamon)-Vol. 20, Iss: 12, pp 1315-1324
TL;DR: In this article, numerical solutions for laminar heat transfer of a non-Newtonian fluid in the thermal entrance region of a square duct are presented for three thermal boundary conditions.
About: This article is published in International Journal of Heat and Mass Transfer.The article was published on 1977-12-01. It has received 85 citations till now. The article focuses on the topics: Nusselt number & Churchill–Bernstein equation.
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01 Jan 2011
TL;DR: In this article, the influence of the rheological parameters on heat transfer enhancement with viscoelastic fluids in the entrance region of tube flow is investigated with negligible axial heat conduction and viscous dissipation.
Abstract: An investigation of heat transfer with viscoelastic fluids in straight pipes of circular and some non-circular cross-sections is carried out. The influence of the rheological parameters on heat transfer enhancement with viscoelastic fluids in the entrance region of tube flow is investigated with negligible axial heat conduction and viscous dissipation. Numerical simulations are conducted with constant wall heat flux for the Graetz problem using the finite element based software Polyflow for viscoelastic fluids of the simplified Phan-Thien Tanner (SPPT) type. It is found that increasing the fluid elasticity, for all cross-sections, raises the normalized heat transfer coefficient for relatively low elasticity values but for high level of fluid elasticity the normalized heat transfer coefficient decreases.Copyright © 2011 by ASME
02 Aug 1999
04 Jan 2011
TL;DR: In this article, experimental and numerical methods were introduced for the investigation of flow phenomena and mass transfer for non-Newtonian fluids in spacer-filled channels, where spacers play an important role in process engineering concerning problems of mixing, homogenizing and dispersing in connection with residence time behavior.
Abstract: Flow and transport phenomena in non-Newtonian fluids are of significant industrial interest. As a kind of static mixer, spacers play an important role in process engineering concerning problems of mixing, homogenizing and dispersing in connection with residence time behavior up to the enhancement of heat and mass transfer. However, the efficiency of such spacers strongly depends on fluid properties, the characteristic geometry and operating conditions. Additionally, it is very difficult to respond to changed operating conditions for such spacers and ill-designed feed spacers can hinder the realization of a high performance.
Here, experimental and numerical methods were introduced for the investigation of flow phenomena and mass transfer for non-Newtonian fluids in spacer-filled channels.
Stromungs- und Transportvorgange in nicht-Newton?schen Flussigkeiten sind von besonderem industriellen Interesse. In der Verfahrenstechnik werden Spacer eingesetzt zur Losung von Problemen beim Mischen, Homogenisieren und Dispergieren, zur Erzielung eines gunstigen Verweilzeitverhaltens sowie zur Steigerung des Stoff- und Warmetransports. Die Effizienz solcher Spacer hangt stark ab von den Fluideigenschaften, von der Spacer-Geometrie und von den Betriebsbedingungen. Deswegen kommt einer Optimierung dieser Spacer fur die jeweiligen Randbedingungen eine wesentliche Rolle zu. Die vorliegende Arbeit befasst sich deswegen mit experimentellen und numerischen Methoden zur Untersuchung der Stromungs- und Transportvorgange in Kanalen mit Spacern fur nicht-Newton?sche Flussigkeiten.
Book•
01 Jan 1981TL;DR: In this article, the authors present a complete reference book on heat and mass transfer, containing extensive information in the form of interesting and realistic examples, problems, charts, tables, illustrations, and more.
Abstract: This complete reference book covers topics in heat and mass transfer, containing extensive information in the form of interesting and realistic examples, problems, charts, tables, illustrations, and more. Heat and Mass Transfer emphasizes practical processes and provides the resources necessary for performing accurate and efficient calculations.This excellent reference comes with a complete set of fully integrated software available for download at crcpress.com, consisting of 21 computer programs that facilitate calculations, using procedures developed in the text. Easy-to-follow instructions for software implementation make this a valuable tool for effective problem-solving.
01 Jan 2006
TL;DR: In this paper, a survey of the developments in heat transfer studies of nonlinear inelastic as well as elastic fluids in tubes is given, where heat transfer enhancement characteristics of viscoelastic aqueous polymer solutions are very significant.
Abstract: A survey of the developments in heat transfer studies of non-linear inelastic as well as elastic fluids in tubes is given. Experimental findings concerning heat transfer enhancement characteristics of viscoelastic aqueous polymer solutions are very significant. Specifically, it is reported that heat transfer results for viscoelastic aqueous polymer solutions are drastically higher than those found for water in laminar flow in rectangular ducts. A number of investigators suggested that the high experimental heat transfer values were due to secondary flows resulting from the elasticity of the fluids. In this context recent results concerning the fully developed thermal field in constant pressure gradient driven laminar flow of a class of viscoelastic fluids characterized by single mode, non-affine constitutive equations in straight pipes of arbitrary contour ∂D is reviewed. Heat transfer enhancement due to shear-thinning is identified together with the enhancement due to the inherent elasticity of the fluid. The latter is the result of secondary flows in the cross-section. Increasingly large enhancements are computed with increasing elasticity of the fluid as compared to its Newtonian counterpart. Large enhancements are possible even with dilute fluids. Isotherms for the temperature field are presented and discussed for several non-circular contours such as the ellipse and the equilateral triangle together with heat transfer behavior in terms of the Nusselt number Nu.Copyright © 2006 by ASME
References
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01 Nov 1971
TL;DR: Theoretical laminar flow solutions for heat transfer and flow friction are of importance in the development of compact heat exchangers as discussed by the authors, generally the higher the degree of compactness, the lower is the Reynolds number and the greater is the relevance of the theory solutions.
Abstract: : Theoretical laminar flow solutions for heat transfer and flow friction are of importance in the development of compact heat exchangers. Generally the higher the degree of compactness, the lower is the Reynolds number and the greater is the relevance of the theory solutions. In the report these solutions are compiled for twenty one straight ducts and four curved ducts. Some new analytical solutions are obtained by writing a general computer program for three ducts. Application of the analytical solutions to the gas turbine regenerator is discussed.
101 citations
01 Jan 2019
18 citations
TL;DR: In this paper, the authors used the momentum and energy integral method of von Karman and Pohlhausen to solve the entrance heat transfer problem for a non-Newtonian fluid in a flat duct.
Abstract: The momentum and energy integral method of von Karman and Pohlhausen is used to solve the entrance heat transfer problem for a non-Newtonian fluid in a flat duct. The initial temperature and velocity profiles are assumed to be flat. The fluid is assumed to obey the Ostwald-de Wael model and its physical properties are assumed to be constant. Dimensionless expressions for temperature and velocity profiles are obtained by numerical methods.
The results of this investigation indicate that, similar to the case of Newtonian fluid, the parameters which influence entrance heat transfer are x/b ratio, Reynolds number and Prandtl number, provided these groups are properly defined.
La methode tenant compte du momentum et de l'energie de von Karman et de Pohlhausen est utilisee pour resoudre le probleme de la transmission de chaleur a l'entree d'un conduit plat pour un fluide non-Newtonien. Les profils initiaux de temperature et vitesse sont supposes uniformes. Le fluide est conforme au modele Ostwald-de Wael et ses proprieties sont supposees constantes. Les expressions sans dimensions sont obtenues a l'aide d'analyses numeriques pour les profils de temperature et vitesse.
Les resultats de cette recherche indiquent que, similarement au cas des fluides non-Newtoniens, les parametres influencant la transmission de chaleur a l'entree, sont x/b, Re et Pr en autant que ces groupes son definis adequatement.
16 citations