Numerical simulation for impact of copper/water nanofluid on thermo-convective instabilities in a horizontal porous annulus

Natural convection and heat transfer inside a porous concentric horizontal cylindrical annulus saturated by a Cu–water nanofluid was investigated in this study. The governing equations were discretized using the finite difference technique and solved using the alternating direction implicit (ADI) me...

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Bibliographic Details
Published in:Journal of thermal analysis and calorimetry 2019-10, Vol.138 (2), p.1515-1525
Main Authors: Belabid, Jabrane, Belhouideg, Soufiane, Allali, Karam, Mahian, Omid, Abu-Nada, Eiyad
Format: Article
Language:English
Subjects:
Alternating direction implicit methods
Analytical Chemistry
Annuli
Bifurcations
Chemistry
Chemistry and Materials Science
Computer simulation
Copper
Finite difference method
Fluid flow
Free convection
Heat transfer
Inorganic Chemistry
Measurement Science and Instrumentation
Nanofluids
Nanoparticles
Numerical analysis
Nusselt number
Physical Chemistry
Polymer Sciences
Porosity
Porous media
Rayleigh number
Viscosity
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Summary:Natural convection and heat transfer inside a porous concentric horizontal cylindrical annulus saturated by a Cu–water nanofluid was investigated in this study. The governing equations were discretized using the finite difference technique and solved using the alternating direction implicit (ADI) method. It was found that the increase in nanoparticles had a favorable effect on the enhancement of the heat transfer for low Rayleigh numbers. However, exceeding a given threshold of Rayleigh number, the addition of nanoparticles had an adverse effect on the heat transfer. Also, the study revealed the effect of porosity on Nusselt number, where the increase in volume fraction of nanoparticles in the porous medium leads to a considerable increase in the Nusselt number ratio when the porosity equals 0.5 and 0.8, an opposite behavior was observed when this latter equals 0.1. The bifurcation between the unicellular and the bicellular regimes was investigated for several nanoparticles volume fractions and a wide range of porosity. The results revealed that regardless of the porosity, the critical Rayleigh number for the transition from the unicellular to the bicellular regime increases with volume fraction of nanoparticles for the whole range of the radius ratio. Several numerical correlations were developed for the critical Rayleigh number in terms of volume fraction of nanoparticles and porosity of the medium.
ISSN:1388-6150
1588-2926
DOI:10.1007/s10973-019-08265-x