Simulation of natural convection of Fe3O4-water ferrofluid in a circular porous cavity in the presence of a magnetic field

This paper presents a numerical study of a double diffusive convection in an inclined square porous cavity filled with an electrically conducting binary mixture. The upper and bottom walls are maintained at a constant temperatures and concentrations whereas the left and right walls are assumed to be adiabatic and impermeable. A uniform and tilted magnetic field is applied at an angle, ?, about the horizontal, it is obvious that this is related to the orientation of the magnetic force that can help or oppose the buoyant force. The Dupuit-Darcy flow model, which includes effects of the inertial parameter, with the Boussinesq approximation, energy and species transport equations are solved numerically using the classical finite difference method. Governing parameters of the problem under study are the thermal Rayleigh number, Rt, Hartmann number, Ha, Lewis number, Le, the buoyancy ratio, ?,inclination angle, ? and tilting angle of the magnetic field, ?,. The numerical results are reported on the contours of streamline, temperature, and concentration and for the average Nusselt and Sherwood numbers for various parametric conditions. It is demonstrated that both the inertial effect parameter and the magnetic field, have a strong influence on the strength of the natural convection heat and mass transfer within the porous layer.

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MHD natural convection in a square porous cavity filled with a water-based magnetic fluid in the presence of geothermal viscosity

International Journal of Numerical Methods for Heat &amp Fluid Flow ◽

10.1108/hff-12-2017-0503 ◽

2018 ◽

Vol 28 (9) ◽

pp. 2111-2131 ◽

Cited By ~ 6

Author(s):

Mikhail A. Sheremet ◽

Marina S. Astanina ◽

Ioan Pop

Keyword(s):

Magnetic Field ◽

Heat Transfer ◽

Natural Convection ◽

Magnetic Fluid ◽

Convective Flow ◽

Uniform Magnetic Field ◽

Vertical Wall ◽

Content Type ◽

Porous Cavity ◽

Water Based

Purpose The purpose of this paper is a numerical analysis of natural convection in a square porous cavity filled with a water-based magnetic fluid of geothermal viscosity under the effect of inclined uniform magnetic field. Design/methodology/approach The domain of interest includes the square porous cavity filled with a water-based magnetic fluid (W40). Horizontal walls are supposed to be adiabatic, while right vertical wall is kept at constant low temperature and left vertical wall is kept at constant high temperature. An inclined uniform magnetic field affects the fluid flow and heat transfer inside the cavity. The viscosity of the working fluid is proportional to the linearly decreasing function of depth (vertical coordinate) and inversely proportional to the linear function of temperature. It is assumed in the analysis that the flow is laminar. The fluid is Newtonian and the Boussinesq approximation is valid. The governing equations have been discretized using the finite difference method with the uniform grid. Simulations have been carried out for different values of the Rayleigh number, Hartmann number, Darcy number, magnetic field inclination angle and viscosity variation parameters. Findings It has been revealed that an increase in the viscosity parameters leads to the heat transfer enhancement and convective flow intensification. At the same time, this intensification is more essential for high values of the Rayleigh number. Originality/value The originality of this work is to analyze MHD natural convection in a square porous cavity filled with a water-based magnetic fluid of geothermal viscosity. The results would benefit scientists and engineers to become familiar with the analysis of convective heat and mass transfer in nanofluids, and the way to predict the properties of nanofluid convective flow in advanced technical systems, in industrial sectors including transportation, power generation, chemical sectors and electronics.

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