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.
Citations
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TL;DR: In this article, the trade-off between heat transfer enhancement and pressure drop produced by the baffles was studied for periodically fully developed flow in a three-dimensional channel with baffles.
Abstract: A numerical investigation of laminar forced convective heat transfer was performed in a three-dimensional channel with baffles in which a uniform heat flux was applied to the top and bottom walls, and the sidewalk were considered adiabatic. The trade-off between heat transfer enhancement and pressure drop produced by the baffles was studied for periodically fully developed flow (PDF). The numerical analysis was performed using a finite volume approach. The computer code was validated against the experimental results of Goldstein and Kreid [1] and Beavers et al. [2] for a three-dimensional channel without baffles. Parametric runs were made for Reynolds numbers of 150, 250, 350, and 450 for baffle height to channel width ratios (H/Dy) of 0.5, 0.6, 0.7, and 0.8. Heat transfer behavior was studied for Prandtl numbers of 0.7 and 7.0, and for wall thermal conductivity to fluid thermal conductivity ratios (K) of 1, 10, 100, and 1000. Address correspondence to Dr. N. K, Anand, Department of Mechanical Engineering...
63 citations
TL;DR: In this paper, a rigorous solution is obtained for the temperature field and the Nusselt numbers in the fully developed thermal region of rectangular ducts, wherein a laminar fully developed velocity profile occurs.
63 citations
TL;DR: In this article, the generalized integral transform (GIFT) was used to solve convection-diffusion problems with non-separable eigenvalue problems in the thermal entry region, for a wide range of axial variable and various aspect ratios.
61 citations
TL;DR: In this article, the authors examined the convective heat transfer of pseudoplastic fluids in a square cavity with a heated bottom and cooled top walls using the Sutterby model and found that the heat transfer rate became larger than that of a Newtonian fluid under thermal conditions where stable vortex flows were formed.
Abstract: The natural convective heat transfer of pseudoplastic fluids in a square cavity with a heated bottom and cooled top walls was examined by a direct numerical analysis using the Sutterby model. Consequently, it could be verified that the heat transfer rate of pseudoplastic fluids became larger than that of a Newtonian fluid under thermal conditions where stable vortex flows were formed. The reason is that fluid flows are easy to further develop particularly near the walls due to the decrease in the apparent viscosity by the shear-thinning effect. On the other hand, it was found that the locally larger change in viscosity had the potential of causing the formation of a complicated flow field when the non-Newtonian fluid was highly pseudoplastic and the Rayleigh number increased. The contribution of the shear-thinning effect depending on the non-Newtonian property and the thermal condition was clearly revealed.
59 citations
TL;DR: In this article, the velocity and temperature distribution in steady state, hydro dynamically and thermally fully developed, laminar forced flow for Newtonian fluids in rectangular ducts were analyzed for all the modified H2 thermal boundary conditions around the periphery of the duct cross-section.
57 citations
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