Entropy generation and natural convection in square cavities with wavy walls

Morsli, Souad; Sabeur-Bendehina, Amina

doi:10.1134/s0021894413060060

Cited by 15 publications

(4 citation statements)

References 11 publications

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“…Meanwhile, decreasing Richardson numbers yielded a linear increment on average Bejan number and total entropy generation. Morsli and Sabeur 20 studied numerically natural convection and entropy production within a 2D square cavity with a hot wavy wall under the laminar flow. The obtained results showed that the entropy level increased for higher Rayleigh numbers and high irreversibility ratios.…”

Section: Introductionmentioning

confidence: 99%

CFD‐based analysis of entropy generation due to mean and fluctuating fields during turbulent natural convection in a square enclosure

2022

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The current study aims to numerically investigate the entropy generation during the natural convection flow of air in a square cavity. The governing equations for the conservation of mass, momentum, energy, and turbulence are solved using a control volume‐based technique employing the commercial code Fluent. Runs have been performed for both laminar and turbulent flow regimes by varying the Rayleigh number (Ra) from 103 to 1010. On the other hand, various viscous distribution coefficients (ϕ = 10−4, 10−3, and 10−2) and constant Prandtl number (Pr = 0.71) were considered. Given the conflicting perspectives in the literature regarding the entropy generation under turbulent regimes, more research is needed to better understand the impact that the fluctuating flow has on entropy production. The four terms of entropy generation inherent to turbulent natural convection (entropy generation due to dissipation in the mean and the fluctuating velocity fields in addition to the heat flux due to the mean and the fluctuating temperature) are computed in the present work and compared to calculations based on only mean values of temperature and velocity gradients. It was found that taking into account the fluctuating terms of temperatures and velocities augment the total entropy generation by 10.10%, 14.43%, and, 17.70%, up to 32.60%, respectively, for Ra = 5 × 108, Ra = 109, Ra = 1.58 × 109, and Ra = 1010. The gain shows the tendency to increase with the Rayleigh number. Thus, the fluctuating terms cannot be neglected particularly for high Rayleigh numbers. Furthermore, unlike entropy production due to the mean flow field, numerical outcomes reveal that the generated irreversibilities due to fluctuating flow are located around the upper hot and the lower cold corners of the heated walls. In addition, a numerical relationship between the first and the second laws of thermodynamics has been derived. A promising result that emerged from this study has shown that the Nusselt number and therefore the first law of thermodynamics is sufficient to estimate the heat part of entropy generation without the necessity of using the second law.

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Section: Introductionmentioning

confidence: 99%

CFD‐based analysis of entropy generation due to mean and fluctuating fields during turbulent natural convection in a square enclosure

2022

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“…In applying EGM, the entropy generation rate and Bejan number are usually computed. EGM has been employed in many complex multi-physical flows in recent years including combustion [36], thermally-stratified porous media flows [37], unsteady variable viscosity polymeric coating flows [38], periodic magnetohydrodynamic convection flows [39], Von Karman swirling flows [40], free convection in wavy enclosures for solar energy [41] and hydromagnetic micropolar channel flows [42]. In nanofluid mechanics, EGM has been applied in optimizing nanoscale slip flows with transpiration [43], stretching sheet nanofluid flows [44] and transient stagnation point flows with simultaneous electrical and magnetic field effects.…”

Section: Introductionmentioning

confidence: 99%

Entropy Analysis of a Convective Film Flow of a Power-Law Fluid with Nanoparticles Along an Inclined Plate

Vasu

Gorla

Murthy

et al. 2019

J Appl Mech Tech Phy

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“…However, enclosures like triangular shaped have received a paramount attention in many practical appliances, for example, thermal environment of buildings, solar energy systems, cooling of electronics equipment, geophysics, nuclear power plant, heat exchanger and many other applications involving heat transfer due to its geometry [1][2][3][4]. Morsil and Sabeur-Bendehina [5] conducted numerical study for natural convection in a wavy square enclosure. It was reported that the Nusselt number was decreased with the undulations.…”

Section: Introductionmentioning

confidence: 99%

Free Convection in a Caterpillar Shaped Triangular Enclosure Filled with Different Nanofluids

Triveni¹,

Panua²

2019

IJHT

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A numerical work is conducted for the free convection in a right triangular cavity filled with water-based nanofluids. The bottom wall is in a caterpillar wavy shape which is assumed as a hot wall whereas the rest walls of the enclosure are considered as a cold wall. Governing equations of the problem are discretized through the finite volume method. The present study is undertaken to appraise the effect of the constrained parameters i.e. various types of nanofluids (TiO2, CuO, and Al2O3), volume fractions of thenanoparticles and Rayleigh number (Ra=10 5 -10 7 ). The higher augmentation in the rate of heat transfer is observed for the Al2O3-water-based nanofluid for each Rayleigh number.

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Entropy generation and natural convection in square cavities with wavy walls

Cited by 15 publications

References 11 publications

CFD‐based analysis of entropy generation due to mean and fluctuating fields during turbulent natural convection in a square enclosure

CFD‐based analysis of entropy generation due to mean and fluctuating fields during turbulent natural convection in a square enclosure

Entropy Analysis of a Convective Film Flow of a Power-Law Fluid with Nanoparticles Along an Inclined Plate

Free Convection in a Caterpillar Shaped Triangular Enclosure Filled with Different Nanofluids

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