The present analysis aims at investigating the effect of a uniform vertical magnetic field on the onset of convection in an electrically conducting nanofluid layer with a new set of physical boundary condition. It is assumed that the value of the temperature can be imposed on the boundaries, but the nanoparticle fraction adjusts together with effects of Brownian and thermophoresis so that the nanoparticle flux is zero on the boundaries. Using the Galerkin method, the critical Rayleigh number on the onset of convection and the corresponding wave number are obtained in terms of various parameters numerically. The numerical computations are presented for water-based nanofluids with Al2O3 and Cu nanoparticles. It is found that the volumetric fraction of nanoparticle, the Lewis number, the modified diffusivity and the density ratios have a destabilizing effect, while the magnetic field has stabilizing effect on the system. The zero flux nanoparticle boundary condition has more destabilizing effect than the constant nanoparticle boundary conditions for Al2O3-water nanofluid, while reverse for Cu-water nanofluid.
|Number of pages||9|
|Journal||Applied Thermal Engineering|
|Publication status||Published - 2016 Jun 25|
Bibliographical noteFunding Information:
This work was supported by the Yonsei University Research Fund of 2014–2015 and the Human Resources Development program (No. 20144030200560) of Korea Institute of Energy Technology Evaluation and Planning (KETEP) grant funded by Korea Government Ministry of Trade.
© 2016 Elsevier Ltd. All rights reserved.
All Science Journal Classification (ASJC) codes
- Energy Engineering and Power Technology
- Industrial and Manufacturing Engineering