Natural convection in a square enclosure with a hot source

Paroncini, M.; Corvaro, Francesco

doi:10.1016/j.ijthermalsci.2009.02.005

Cited by 98 publications

(55 citation statements)

References 9 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Conversely the right zone is split into two smaller zones. The impact of buoyancy on isotherms is similar to the results reported by Oh et al and Paroncini and Corvaro …”

Section: Cfd Simulation Resultssupporting

confidence: 89%

Computational study of heat transfer in solar collectors with different radiative flux models

Kuharat

Bég

Kadir

et al. 2019

Heat Trans. Asian Res.

View full text Add to dashboard Cite

Two-dimensional steady incompressible laminar Newtonian viscous convection-radiative heat transfer in a rectangular solar collector geometry is considered. The ANSYS FLUENT finite volume code (version 17.2) is used to simulate the thermo-fluid characteristics. Extensive details of computational methodology are given to provide engineers with a framework for simulating radiative-convection in enclosures. Meshindependence tests and validation are conducted. The influence of aspect ratio, Prandtl number (Pr), Rayleigh number (Ra) and radiative flux model on temperature, isotherms, velocity, and pressure is evaluated and visualized in colour plots. In addition, local convective heat flux is computed, and solutions are compared with the MAC solver for various buoyancy effects achieving excellent agreement. The P1 model is shown to better predict the actual influence of solar radiative flux on thermal fluid behaviour compared with the limited Rosseland model. With increasing Ra, the hot zone emanating from the base of the collector is found to penetrate deeper into the collector and rises symmetrically dividing into two vortex regions with very high buoyancy effect. With increasing Pr there is a progressive incursion of the hot zone at the solar collector base higher into the solar collector space and simultaneously a greater asymmetric behaviour of the dual isothermal zones.ANSYS FLUENT, aspect ratio, inite volume, MAC computational algorithm, radiative heat transfer, solar collector enclosure, thermal convection 1 | INTRODUCTION The interest in sustainable and renewable energy systems has witnessed significant expansion in the 21st century. Both land-based (terrestrial) and space-based (astronautical) types of solar collector have attracted considerable attention. Solar thermal collectors utilize the incoming radiation by converting it directly into heat whereas photovoltaics convert the radiation into electricity. Solar thermal systems therefore offer many desirable characteristics for propulsion, water and space heating.Space solar power collectors have multiple advantages over earth-based solar power plants. They receive more sun light, are unaffected by weather, free from the day-night cycle, and expensive storage can be avoided. 1,2 The types of geometric designs, which have been developed for spacecraft solar collectors, are generally similar to those of terrestrial systems. They invariably feature an enclosure (cavity) in which the solar radiation initiates and sustains a circulation flow field. The thermo-physics inevitably involves all three modes of heat transfer (conduction, convection, and radiation) although the individual contributions may vary with the particular design adopted, as elaborated by Kreith. 3 Several studies have confined attention to thermal conduction and radiation in spacecraft solar collectors, including Yang et al, 4 who studied three-dimensional anisotropic conduction and a simple radiation network model for collectors in deep cold space. The key mechanism in fluid-based solar collec...

show abstract

“…Conversely the right zone is split into two smaller zones. The impact of buoyancy on isotherms is similar to the results reported by Oh et al and Paroncini and Corvaro …”

Section: Cfd Simulation Resultssupporting

confidence: 89%

Computational study of heat transfer in solar collectors with different radiative flux models

Kuharat

Bég

Kadir

et al. 2019

Heat Trans. Asian Res.

View full text Add to dashboard Cite

show abstract

“…Similar conclusion is mentioned by Paroncini and Corvaro (2009). Through plots, the symmetric behaviour of the fluid flow is observed.…”

Section: Effect Of Block Heightsupporting

confidence: 86%

“…It can be seen that contours plots are symmetric for different spacing and the convection heat transfer is dominant over conduction owing to higher values of Rayleigh number. When heat sources are closer to each other (D = 0.1), thermal structure is almost identical to a thermal plume generated by a single hot block (Paroncini and Corvaro., 2009;Naffouti et al, 2013) while the flow field is described by two big counter-rotating cells. However, the ascending hot air is strongly entrained by the cold air which comes by the low from the sides causing a strong interaction of the resulting flow.…”

Section: Effect Of Spacing Between Heat Blocksmentioning

confidence: 95%

Applied Thermal Lattice Boltzmann Model for Fluid Flow of Free Convection in 2-D Enclosure with Localized Two Active Blocks: Heat Transfer Optimization

Naffouti

Zinoubi

Sidik³

et al. 2016

JAFM

View full text Add to dashboard Cite

The aim of this paper is to analyze the laminar free convective flow generated by two identical hot blocks in two-dimensional enclosure cooled by the sides in order to optimize the heat transfer. The top wall and the flat surfaces on bottom wall are adiabatic except for the active sources located symmetrically. Each source of a rectangular form is heated at a uniform temperature while the Prandtl number is fixed at 0.71. Thermal Lattice Boltzmann model of D2Q4-D2Q9 is applied to solve the thermal flow problem. Numerical simulations have been conducted to reveal the effects of various parameters; Rayleigh number 10 3 ≤ Ra ≤ 10 6 , spacing between blocks 0.1 ≤ D ≤ 0.6, block height 0.05 ≤ H ≤ 0.4 and aspect ratio of the enclosure 1 ≤ A ≤ 4 on fluid flow and heat transfer. The computational results by Lattice Boltzmann method have been found to be in good agreement with previous works. The results are presented in the form of isotherms and streamlines plots as well as the variation of the average Nusselt number along horizontal and vertical hot walls. It is found that increasing Rayleigh number and distance between active blocks enhance the heat transfer. The simulations show that the block height and aspect ratio are the most important parameters affecting dynamic and thermal fields and consequently the heat transfer efficiency in the enclosure.

show abstract

“…Several theoretical and experimental studies have also been devoted to the horizontal annulus, as summarized in [3]. For more complex configurations, though most of the effort has been mainly focused on heat transfer performances [4][5][6][7], the use of optical techniques such as Particle Image Velocimetry (PIV), has recently allowed the experimental study of the flow field and of its influence on the overall heat transfer [8,9]. Several authors also dealt with natural convection from enclosed heat sources with the use of state-ofthe-art numerical techniques [6,7,[10][11][12].…”

Section: Introductionmentioning

confidence: 99%

Appearance of quasiperiodicity within a period doubling route to chaos of a swaying thermal plume

Angeli

Corticelli

Fichera

et al. 2014

J. Phys.: Conf. Ser.

View full text Add to dashboard Cite

Natural convection in a square enclosure with a hot source

Cited by 98 publications

References 9 publications

Computational study of heat transfer in solar collectors with different radiative flux models

Computational study of heat transfer in solar collectors with different radiative flux models

Applied Thermal Lattice Boltzmann Model for Fluid Flow of Free Convection in 2-D Enclosure with Localized Two Active Blocks: Heat Transfer Optimization

Appearance of quasiperiodicity within a period doubling route to chaos of a swaying thermal plume

Contact Info

Product

Resources

About