Heat transfer enhancement of Fe3O4 ferrofluids in the presence of magnetic field

Fadaei, F ; Sharif University of Technology | 2017

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  1. Type of Document: Article
  2. DOI: 10.1016/j.jmmm.2017.01.046
  3. Publisher: Elsevier B.V , 2017
  4. Abstract:
  5. In this article, three-dimensional (3D) forced-convection heat transfer of magnetic nanofluids in a pipe subject to constant wall heat flux in the presence of single or double permanent magnet(s) or current-carrying wire has been investigated and compared. In this regard, laminar fluid flow and equilibrium magnetization for the ferrofluid were considered. In addition, variations of magnetic field in different media were taken into account and the assumption of having a linear relationship of magnetization with applied magnetic field intensity was also relaxed. Effects of magnetic field intensity, nanoparticle volume fraction, Reynolds number value, and the type of magnetic field source (i.e., a permanent magnet or current-carrying wire) on the forced-convection heat transfer of magnetic nanofluids were carefully investigated. It was found that by applying the magnetic field, the fluid mixing could be intensified that leads to an increase in the Nusselt number value along the pipe length. Moreover, the obtained simulation results indicate that applying the magnetic field induced by two permanent magnets with a magnetization of 3×105 (A/m) (for each one), the fully developed Nusselt number value can be increased by 196%. © 2017 Elsevier B.V
  6. Keywords:
  7. Current carrying wire, Heat-transfer enhancement ; Ferrofluid ; Nanofluid ; Permanent magnet ; Electric wire ; Flow of fluids ; Forced convection ; Heat convection ; Heat flux ; Heat transfer coefficients ; Magnetic field effects ; Magnetic fluids ; Magnetism ; Magnetization ; Magnets ; Nanofluidics ; Nanomagnetics ; Nanoparticles ; Nusselt number ; Permanent magnets ; Reynolds number ; Wire ; Applied magnetic fields ; Constant wall heat flux ; Convective heat transfer ; Equilibrium magnetization ; Heat Transfer enhancement ; Magnetic-field intensity ; Nanofluids ; Nanoparticle volume fractions ; Heat transfer
  8. Source: Journal of Magnetism and Magnetic Materials ; Volume 429 , 2017 , Pages 314-323 ; 03048853 (ISSN)
  9. URL: https://www.sciencedirect.com/science/article/pii/S0304885316324702?via%3Dihub