scispace - formally typeset
Search or ask a question
Journal ArticleDOI

Laminar forced convection heat transfer of a non-newtonian fluid in a square duct

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
More filters
Journal ArticleDOI
TL;DR: In this article, the characteristics of convective heat transfer and fluid flow within a square cross-section serpentine channel are experimentally studied for two groups of polymeric viscoelastic fluids, shear-thinning and constant-viscosity Boger solutions.
Abstract: The characteristics of convective heat transfer and fluid flow within a square cross-section serpentine channel are experimentally studied for two groups of polymeric viscoelastic fluids, shear-thinning and constant-viscosity Boger solutions. The elastic turbulence can be created by the non-linear interaction between elastic stresses generated within the flowing high-molecular-weight polymer solutions and the streamline curvature. In order to confirm elastic turbulence in this geometry, pressure drop across the serpentine channel was measured. The findings indicate that the measurements of non-dimensional pressure-drop increase approximately from 1.48 to 4.82 for viscoelastic solutions compared with the Newtonian fluid over a range of Weissenberg number from 4 to 211. The convective heat transfer enhances due to elastic turbulence by up to 200% for low polymer concentration (dilute) solutions and reaches up to 380% for higher polymer concentration (semi-dilute) solutions under creeping-flow conditions in comparison to that achieved by the equivalent Newtonian fluid flow at low Graetz number (up to 14.6). We propose a modified Weissenberg number which is able to approximately collapse the mean Nusselt number data for each solution group.

56 citations


Cites background or methods from "Laminar forced convection heat tran..."

  • ...As will be shown, the agreement between the averaged Nu rom the present experiments for Newtonian fluids and numerical ata [23,24] (see Fig....

    [...]

  • ...The averaged Nu for Newtonian fluid flow collapses to the numerical predictions [24] for a thermallydeveloping laminar flow through a straight square duct under the condition of constant wall temperature....

    [...]

Journal ArticleDOI
TL;DR: In this paper, the authors conducted a survey on numerical heat transfer and found that the majority of the participants were satisfied with the number of heat transfers performed by the algorithm, but not with the accuracy.
Abstract: (1982). A LITERATURE SURVEY ON NUMERICAL HEAT TRANSFER. Numerical Heat Transfer: Vol. 5, No. 4, pp. 369-420.

50 citations

Journal ArticleDOI
TL;DR: In this paper, the effects of fluid refrigerant and channel geometry on the frictional pressure drop during two-phase flow inside micro-channels were investigated for the refrigerants R134a, R1234ze(E), R 1234yf and R600a in a circular channel and for R 134a in square and triangular channels.
Abstract: An investigation was conducted on the effects of fluid refrigerant and channel geometry on the frictional pressure drop during two-phase flow inside microchannels. Experimental results for two-phase frictional pressure drop were obtained for the refrigerants R134a, R1234ze(E), R1234yf and R600a in a circular channel and for R134a in square and triangular channels. The experiments were performed for mass velocities from 100 to 1600 kg m −2 s −1 , saturation temperatures of 31 and 41 °C, and vapor qualities from 0.05 to 0.95. The experimental data have been analyzed focusing on the effects of the geometry and fluid on the two-phase pressure drop. Then, the data were compared with the most quoted predictive methods from the literature. Based on the broad database obtained, a new method for prediction of the two-phase frictional pressure drop was proposed. The new method provided accurate predictions of the database, predicting 89% of the results within an error band of ±20%.

50 citations

Journal ArticleDOI
TL;DR: In this article, the authors present general equations for heat transfer calculations for constant wall temperature in laminar developed flow in ducts of arbitrary cross sections and compare the results obtained from these equations with the theoretically-calculated values available in the literature for circular, rectangular, triangular, elliptical and parallel plate ducts.

50 citations

Journal ArticleDOI
TL;DR: In this article, the effects of fluid rheology (pseudoplasticity or dilatancy), duct geometry, and thermal boundary conditions on the velocity and temperature field, are delineated.

47 citations

References
More filters
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

Proceedings ArticleDOI
01 Jan 2019

18 citations

Journal ArticleDOI
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