Effect of Magnetic Field and Wall Conductivity on Conjugate Natural Convection in a Square Enclosure

2014 ◽  
Vol 39 (6) ◽  
pp. 4977-4989 ◽  
Author(s):  
Abdennacer Belazizia ◽  
Smail Benissaad ◽  
Said Abboudi
Author(s):  
Ammar I. Alsabery ◽  
Tahar Tayebi ◽  
Ali J. Chamkha ◽  
Ishak Hashim

Purpose The purpose of this paper is to study problem of conjugate MHD natural convection of Al2O3-water nanofluid in a square cavity with conductive inner block using Buongiorno’s two-phase model numerically. Design/methodology/approach An isothermal heater is placed on the left wall of the square cavity, while the right wall is maintained at a constant cold temperature. The horizontal top and bottom walls are kept adiabatic. The boundaries of the annulus are assumed to be impermeable, the fluid within the cavity is a water-based nanofluid having Al2O3 nanoparticles. The Boussinesq approximation is applicable. The governing equations subject to the boundary conditions are solved using the finite difference method. Findings Numerical results are presented graphically in the form of streamlines, isotherms and nanoparticles distributions as well as the local and average Nusselt numbers. The results show that the effect of the nanoparticles addition on the average Nusselt number is essential for low Rayleigh, high Hartmann and high values of length ratio when attenuated the convective flow. Originality/value According to exist studies and to the authors’ best knowledge, so far, there have been no studies of conjugate natural convection of Al2O3-water nanofluid in a square cavity with a conductive inner block using Buongiorno’s two-phase model with the effect of the magnetic field. Thus, the authors believe that this work is new and valuable. The aim of this study is to investigate the MHD natural convection of Al2O3-water nanofluid in a square cavity with conductive inner block using Buongiorno’s two-phase model.


2014 ◽  
Vol 6 ◽  
pp. 873260 ◽  
Author(s):  
Kewei Song ◽  
Toshio Tagawa ◽  
Liang-bi Wang ◽  
Hiroyuki Ozoe

Numerical computations are carried out for natural convection of air in a two-dimensional square enclosure under a nonuniform magnetic field and together with the gravity field. The nonuniform magnetic field is supplied by a cubic permanent magnet placed above the enclosure. Two kinds of the expressions for the magnetizing force are considered and compared in the numerical computations. The flow and temperature fields, the magnetizing force field and the Nusselt number for two kinds of magnetizing force expressions are all presented in this paper. The numerical results reveal that the natural convection inside the enclosure does not depend on the types of the expressions for magnetizing force.


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