Effect of magnetic fields on heat convection inside a concentric annulus filled with Al2O3-water nanofluid

A. Malvandi*, S. A. Moshizi, D. D. Ganji

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

53 Citations (Scopus)

Abstract

In the current study, forced convective heat transfer of an MHD fully developed laminar nanofluid between two concentric horizontal cylinders is investigated in the presence of a radial magnetic field. In contrast to a conventional no-slip condition at the surfaces, the Navier's slip condition is considered at the surface to represent the non-equilibrium region near the surfaces. Employing the modified Buongiorno model, the conservative partial differential equations have been collapsed to two-point ordinary boundary value differential equations before being numerically solved. To consider the effects of thermal boundary condition on nanoparticle migration, two distinctive cases including constant heat flux at the outer wall and adiabatic inner wall (Case A) and constant heat flux at the inner wall with adiabatic outer wall (Case B) have been considered. Our results indicate that due to thermophoresis force, the distribution of nanoparticles was denser at the adiabatic wall for the case A which affects the local and the universal fluid flow and heat transfer characteristics. Moreover, inducing a radial magnetic field on the system, heat transfer rate was increased for the case A which had a decreasing effect on the case B. Finally, slip velocity at the walls enhances heat transfer rate for both cases.

Original languageEnglish
Pages (from-to)1817-1824
Number of pages8
JournalAdvanced Powder Technology
Volume25
Issue number6
DOIs
Publication statusPublished - Nov 2014
Externally publishedYes

Keywords

  • MHD
  • Thermophoresis
  • Nanofluid
  • Nanoparticles migration
  • Modified Buongiorno's model

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