Combined Effects of Radiation and Natural Convection in a Square Cavity Submitted to Two Combined Modes of Cross Gradients of Temperature

Ayachi, Rachid El; Raji, A.; Hasnaoui, M.; Naïmi, Mohamed; Abdelbaki, Abdelhalim

doi:10.1080/10407782.2012.712463

Cited by 14 publications

(5 citation statements)

References 23 publications

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“…In general, when natural convection mechanism is considered, radiation may have considerable effects. However, in some case, these effects can be neglected (low temperatures involved and or boundaries with very low emissivity or when the used fluid is assumed to be perfectly transparent to radiation) [16][17][18]. In the present study, since we are interested in flows induced by small temperature levels, radiation and viscous dissipation effects are ignored.…”

Section: Mathematical Modelmentioning

confidence: 99%

Determination of a Hopf bifurcation of natural convection in a symmetric heated square cavity

Kholai¹,

Debbah²,

Filali³

2018

IJHT

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In the present study, numerical investigation is carried out to analyze natural convection in symmetrically heated square cavity filled with air. Left, right and bottom walls are heated partially, whereas remaining portions of these walls are maintained at a lower constant temperature with an isolated top wall. Governing equations are solved by a finite volume method and the analysis is conducted for different Rayleigh number Ra values ranged between 10 3 and 9x10 6. The objective of the present study is to determine the critical Rayleigh number in which a transition from a stationary to an oscillatory flow takes place. The effect of the heating sources placed symmetrically at the two opposite sidewalls in addition to the heating source at the bottom wall was investigated. Results are presented in terms of streamlines, isotherms, and flow variables including the velocity and, temperature profiles and, Fourier frequency spectrum of the temperature. Obtained results shown that for Rayleigh numbers smaller than Racr = 3 × 10 6 , the flow inside the cavity remains stationary with perfectly symmetric patterns. Whereas, beyond this critical value, the system bifurcates in which the flow symmetry is broken and a first Hopf time dependent periodic flow patterns take place.

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Section: Mathematical Modelmentioning

confidence: 99%

Determination of a Hopf bifurcation of natural convection in a symmetric heated square cavity

Kholai¹,

Debbah²,

Filali³

2018

IJHT

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“…Several studies have been carried out in the area of coupled radiation and natural convection. Some of these investigate the coupling between surface radiation and natural convection by considering a transparent medium [1,2]. However, in numerous real engineering problems where the medium involves participating gases such as H 2 O vapor or CO 2 , the volumetric radiation cannot be neglected even at a low temperatures [3,4].…”

Section: Introductionmentioning

confidence: 99%

Interaction of radiation with double-diffusive natural convection in a three-dimensional cubic cavity filled with a non-gray gas mixture in cooperating cases

Cherifi

Laouar-Meftah

Benbrik

et al. 2015

Numerical Heat Transfer, Part A: Applications

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A three-dimensional (3D) numerical study has been performed to investigate the effects of non-gray gas radiation on double-diffusive natural convection in a cubic enclosure filled with either air-H 2 O or air-CO 2 mixtures in cooperating situations. Gas radiation was taken into account by the discrete ordinates method (DOM) associated with the spectral line weighted-sum-ofgray-gases (SLW) spectral model. Results obtained for two average concentrations of H 2 O and CO 2 (10% and 20%) show that radiation modifies the temperature and concentration structures by creating oblique stratifications. The heat transfer rate is decreased, whereas mass transfer is not much modified. In addition, a comparison between 2D and 3D results is presented. ARTICLE HISTORY

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“…The obtained results show a significant impact of the heat radiation on the energy transport. Thermal convection and radiation in the square chamber has been examined by Ayachi et al (2012). The cavity has been deferentially heated and cooled by two configurations, namely, vertical-bottom and vertical-top heated elements.…”

Section: Introductionmentioning

confidence: 99%

Thermal convection and radiation in a rotating cabinet with time-dependent heat-generated solid element and heat-conducting solid walls

Mikhailenko

Ghalambaz

Sheremet

2021

HFF

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Purpose This paper aims to study numerically the simulation of convective–radiative heat transfer under an effect of variable thermally generating source in a rotating square chamber. The performed analysis deals with a development of passive cooling system for the electronic devices. Design/methodology/approach The domain of interest of size H rotating at a fixed angular velocity has heat-conducting solid walls with a constant cooling temperature for the outer boundaries of the vertical walls and with thermal insulation for the outer borders of the horizontal walls. The chamber has a heater on the bottom wall with a time-dependent volumetric heat generation. The internal surfaces of the walls and the energy element are both grey diffusive emitters and reflectors. The fluid is transparent to radiation. Computational model has been written using non-dimensional parameters and worked out by the finite difference technique. The effect of the angular velocity, volumetric heat generation frequency and surface emissivity has been studied and described in detail. Findings The results show that growth of the surface emissivity leads to a diminution of the mean heater temperature, while a weak rotation can improve the energy transport for low volumetric thermal generation frequency. Originality/value An efficient computational approach has been used to work out this problem. The originality of this work is to analyze complex (conductive–convective–radiative) energy transport in a rotating system with a local element of time-dependent volumetric heat generation. To the best of the authors’ knowledge, an interaction of major heat transfer mechanisms in a rotating system with a heat-generating element is scrutinized for the first time. The results would benefit scientists and engineers to become familiar with the analysis of complex heat transfer in rotating enclosures with internal heat-generating units, and the way to predict the heat transfer rate in advanced technical systems, in industrial sectors including transportation, power generation, chemical sectors and electronics.

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Combined Effects of Radiation and Natural Convection in a Square Cavity Submitted to Two Combined Modes of Cross Gradients of Temperature

Cited by 14 publications

References 23 publications

Determination of a Hopf bifurcation of natural convection in a symmetric heated square cavity

Determination of a Hopf bifurcation of natural convection in a symmetric heated square cavity

Interaction of radiation with double-diffusive natural convection in a three-dimensional cubic cavity filled with a non-gray gas mixture in cooperating cases

Thermal convection and radiation in a rotating cabinet with time-dependent heat-generated solid element and heat-conducting solid walls

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