Numerical investigation on natural convection of Al2O3/water nanofluid with variable properties in an annular enclosure under magnetic field
| Autor: | Smail Benissaad, Cherifa Abid, Farid Berrahil, Abdelkader Filali, Omar Matar, Rachid Bessaïh |
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| Přispěvatelé: | Université Abdelhafid Boussouf [Mila], Ecole Nationale polytechnique de Constantine (ENPC), Institut universitaire des systèmes thermiques industriels (IUSTI), Aix Marseille Université (AMU)-Centre National de la Recherche Scientifique (CNRS), Université frères Mentouri Constantine I (UMC) |
| Jazyk: | angličtina |
| Rok vydání: | 2021 |
| Předmět: |
[PHYS]Physics [physics]
Materials science Natural convection Condensed matter physics Lorentz forces General Chemical Engineering Heat transfer enhancement Condensed Matter Physics Nusselt number Atomic and Molecular Physics and Optics Magnetic field Viscosity Nanofluid Volume fraction Annulus (firestop) NOMENCLATURE Mechanical Engineering & Transports annulus enclosure variable properties 0913 Mechanical Engineering |
| Zdroj: | International Communications in Heat and Mass Transfer International Communications in Heat and Mass Transfer, 2021, 126, pp.105408. ⟨10.1016/j.icheatmasstransfer.2021.105408⟩ |
| ISSN: | 0735-1933 |
| DOI: | 10.1016/j.icheatmasstransfer.2021.105408⟩ |
| Popis: | Numerical investigation of the natural convection of Al2O3-water nanofluid is carried out in a differentially heated vertical annulus under a uniform magnetic field. An in-house Fortran code has been developed to solve the system of equations governing the magneto-hydrodynamic flow. Computations are carried out for different Rayleigh numbers (104 ≤ Ra ≤ 106), nanoparticle diameter (dp = 13 and 47 nm), nanoparticle volume fraction (0 ≤ φ ≤ 0.09), radius ratio (2 ≤ λ ≤ 10), and different Hartmann numbers (0 ≤ Ha ≤ 100). According to the simulation data, nanoparticle size is crucial for evaluating nanofluid properties, such as viscosity and thermal conductivity. The computational results reveal that, for nanoparticles with a diameter dp = 47 nm, the average Nusselt number Nu ¯ i on the inner cylinder wall decreases as the nanofluid volume fraction increases. This decrease in Nu ¯ i number is observed up to a volume fraction φ = 0.05, after which it increases again. For the full range of volumetric fractions, it is shown that increasing Ra number causes Nu ¯ i to increase, while increasing Ha number and increasing the magnetic field causes Nu ¯ i to decrease. Furthermore, as the Ha number increases, the heat transfer enhancement ratio En increases mainly when the magnetic field is oriented radially. Finally, new correlations of Nu ¯ i versus Ra, φ, Ha, and λ are derived for the axial and radial magnetic fields cases. |
| Databáze: | OpenAIRE |
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