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Journal ArticleDOI

Influence of wavy wall and non-uniform heating on natural convection heat transfer and entropy generation inside porous complex enclosure

TL;DR: In this paper, the authors numerically analyzed the heat transfer and entropy generation characteristics in a two-dimensional porous right-angled triangular enclosure with undulations on the left wall and found that for lower values of Rayleigh number, heat transfer is dominated by conduction mechanism.
About: This article is published in Energy.The article was published on 2015-01-01. It has received 114 citations till now. The article focuses on the topics: Rayleigh number & Natural convection.
Citations
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Journal ArticleDOI
TL;DR: In this paper, a review of the studies on natural convection heat transfer in triangular, trapezoidal, parallelogrammic enclosures and enclosures with curved and wavy walls filled with fluid or porous media is presented.

168 citations

Journal ArticleDOI
TL;DR: In this paper, the authors investigated the effect of different shaped obstacles (circular, square and diamond) installed under the influence of a uniform magnetic field and uniform heat generation was numerically investigated.
Abstract: In this study, natural convection in a nano-fluid filled cavity having different shaped obstacles (circular, square and diamond) installed under the influence of a uniform magnetic field and uniform heat generation was numerically investigated. The cavity was heated from below and cooled from the vertical sides while the top wall was assumed to be adiabatic. The temperatures of the side walls vary linearly. The governing equations were solved by using Galerkin weighted residual finite element formulation. The numerical investigation was performed for a range of parameters: external Rayleigh number (104 ≤ RaE ≤ 106), internal Rayleigh number (104 ≤ RaI ≤ 106), Hartmann number (0 ≤ Ha ≤ 50), and solid volume fraction of the nanofluid (0 ≤ ϕ ≤ 0.05). It is observed that the presence of the obstacles deteriorates the heat transfer process and this is more pronounced with higher values of Re E . Averaged heat transfer reduces by 21.35%, 32.85% and 34.64% for the cavity with circular, diamond and squared shaped obstacles compared to cavity without obstacles at RaI = 106. The effect of heat transfer reduction with square and diamond shaped obstacles compared to case without obstacle is less effective with increasing values of Hartmann number. Second law analysis was also performed by using different measures for the normalized total entropy generation.

136 citations

Journal ArticleDOI
TL;DR: In this article, the entropy generation in natural convection of nanofluid in a wavy cavity using a single-phase model was analyzed using the finite difference method of the second-order accuracy.
Abstract: Purpose The main purpose of this numerical study is to study on entropy generation in natural convection of nanofluid in a wavy cavity using a single-phase nanofluid model. Design/methodology/approach The cavity is heated non-uniformly from the wavy wall and cooled from the right side while it is insulated from the horizontal walls. The physical domain of the problem is transformed into a rectangular geometry in the computational domain using an algebraic coordinate transformation by introducing new independent variables ξ and η. The governing dimensionless partial differential equations with corresponding initially and boundary conditions were numerically solved by the finite difference method of the second-order accuracy. The governing parameters are Rayleigh number (Ra = 1000-100000), Prandtl number (Pr = 6.82), solid volume fraction parameter of nanoparticles (φ = 0.0-0.05), aspect ratio parameter (A = 1), undulation number (κ = 1-3), wavy contraction ratio (b = 0.1-0.3) and dimensionless time (τ = 0-0.27). Findings It is found that the average Bejan number is an increasing function of nanoparticle volume fraction and a decreasing function of the Rayleigh number, undulation number and wavy contraction ratio. Also, an insertion of nanoparticles leads to an attenuation of convective flow and enhancement of heat transfer. Originality The originality of this work is to analyze the entropy generation in natural convection within a wavy nanofluid cavity using single-phase nanofluid model. The results would benefit scientists and engineers to become familiar with the flow behaviour of such nanofluids, and will be a way to predict the properties of this flow for the possibility of using nanofluids in advanced nuclear systems, in industrial sectors including transportation, power generation, chemical sectors, ventilation, air-conditioning, etc.

128 citations

Journal ArticleDOI
TL;DR: In this paper, the authors investigated the effect of nanofluid concentration on heat transfer and entropy generation in a square porous enclosure, considering temperature dependence of viscosity and viscous dissipation.

116 citations

Journal ArticleDOI
31 Dec 2015-Entropy
TL;DR: It is observed that an insertion of nanoparticles leads to enhancement of heat transfer and attenuation of convective flow inside the cavity.
Abstract: A computational work has been performed in this study to investigate the effects of solid isothermal partition insertion in a nanofluid filled cavity that is cooled via corner isothermal cooler. Mathematical model formulated in dimensionless primitive variables has been solved by finite volume method. The study is performed for different geometrical ratio of solid inserted block and corner isothermal cooler, Rayleigh number and solid volume fraction parameter of nanoparticles. It is observed that an insertion of nanoparticles leads to enhancement of heat transfer and attenuation of convective flow inside the cavity.

109 citations

References
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Book
01 Jan 1992
TL;DR: In this paper, an introduction to convection in porous media assumes the reader is familiar with basic fluid mechanics and heat transfer, going on to cover insulation of buildings, energy storage and recovery, geothermal reservoirs, nuclear waste disposal, chemical reactor engineering and the storage of heat-generating materials like grain and coal.
Abstract: This introduction to convection in porous media assumes the reader is familiar with basic fluid mechanics and heat transfer, going on to cover insulation of buildings, energy storage and recovery, geothermal reservoirs, nuclear waste disposal, chemical reactor engineering and the storage of heat-generating materials like grain and coal. Geophysical applications range from the flow of groundwater around hot intrusions to the stability of snow against avalanches. The book is intended to be used as a reference, a tutorial work or a textbook for graduates.

5,570 citations

Book
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1,838 citations

BookDOI
23 Jun 2015
TL;DR: Theoretical analysis of transport in Porous Media: Multiscale Modeling of Porous Medium Systems as discussed by the authors is a multiscale approach for modelling Porous medium systems.
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1,560 citations

Book
07 Sep 1998
TL;DR: In this paper, the authors present a reference record created on 2004-09-07, modified on 2016-08-08, and used for the purpose of a reference document.
Abstract: Keywords: transport: : : ; matieres: poreuses: : : ; chaleur: transfert de: : : ; masse: transfert de: : : Reference Record created on 2004-09-07, modified on 2016-08-08

1,228 citations

Journal ArticleDOI
TL;DR: The 1985 Advanced Study Institute on Fundamentals of Transport Phenomena in Porous Media (ASI) as discussed by the authors was a sequel to the first ASCI, which was a combination of a conference of experts and a teaching institute.
Abstract: The Advanced Study Institute on Fundamentals of Transport Phenomena in Porous Media, held July 14–23, 1985 in Newark, Del. and directed by Jacob Bear (Israel Institute of Technology, Haifa) and M. Yavuz Corapcioglu (City College of New York), under the auspices of NATO, was a sequel to the NATO Advanced Study Institute (ASI) held in 1982 (proceedings published as Fundamentals of Transport Phenomena in Porous Media, J. Bear, and M.Y. Corapcioglu (Ed.), Martinus Nijhoff, Dordrecht, the Netherlands, 1984). The meeting was attended by 106 participants and lecturers from 21 countries. As in the first NATO/ASI, the objective of this meeting—which was a combination of a conference of experts and a teaching institute— was to present and discuss selected topics of transport in porous media. In selecting topics and lecturers, an attempt was made to bridge the gap that sometimes exists between research and practice. An effort was also made to demonstrate the unified approach to the transport of mass of a fluid phase, components of a fluid phase, momentum, and heat in a porous medium domain. The void space may be occupied by a single fluid phase or by a number of such phases; each fluid may constitute a multicomponent system; the solid matrix may be deformable; and the whole process of transport in the system may take place under nonisothermal conditions, with or without phase changes. Such phenomena are encountered in a variety of disciplines, e.g., petroleum engineering, civil engineering (in connection with groundwater flow and contamination), soil mechanics, and chemical engineering. One of the goals of the 1985 NATO/ASI, as in the 1982 institute, was to bring together experts from all these disciplines and enhance communication among them.

1,119 citations