Browsing by Author "Mouna Maache Battira, Rachid Bessaih"

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    Radial and Axial Magnetic Fields Effects on Natural Convection in a Nanofluid-filled Vertical Cylinder
    (Isfahan University of Technology, 2016-02-12) Mouna Maache Battira, Rachid Bessaih
    This work aims to study numerically the steady natural convection in a vertical cylinder filled with an Al2O3 nanofluid under two different external magnetic fields (Br, Bz) either in the radial or axial directions. The cylinder having an aspect ratio H/R0=1 is bounded by the top and the bottom disks at temperatures Tc and Th, and by an adiabatic side wall. The equations of continuity, Navier-Stokes and energy are non-dimensionalized and then discretized by the finite volume method. A computer program based on the SIMPLER algorithm is developed and compared with the numerical results found in the literature. The effects of nano-size solid volume fraction ranging from 0 to 0.1 and application of the magnetic field in either directions axial and radial for various values of Hartmann numbers on flow and thermal fields, and on local and average Nusselt numbers are presented and discussed for two values of Rayleigh numbers (Ra=103 and 104). The behaviors of average Nusselt number, streamlines, temperature contours, and the both components of velocity are illustrated. The results indicate that for small values of the Hartmann number, where the flow remains due to the convection, the average Nusselt number decreases when increasing the solid volume fraction and this decrease is more important if the magnetic field is applied in the axial direction and by increasing the Hartmann numbers. The increasing in the solid volume fraction increases the performance of heat transfer in the nanofluid.
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    Three-Dimensional Natural Convection in the Horizontal Bridgman Configuration Under Various Wall Electrical Conductivity and Magnetic Field
    (Taylor & Francis, 2008-12-22) Mouna Maache Battira, Rachid Bessaih
    A numerical investigation of the three-dimensional natural convection of a liquid metal contained in the horizontal Bridgman configuration, having an aspect ratio equal to 5 and submitted to an external magnetic field in either the longitudinal or vertical direction, is presented. The numerical approach is based on the finite-volume approximation. A computer program based on the SIMPLER algorithm is developed. The effect of a magnetic field provides a notable change on the flow and thermal structures. The strongest stabilization of the convection flow is found when the magnetic field is oriented vertically. Also, wall electrical conductivity has an effect on the average Nusselt number. A good agreement between our numerical simulations and experimental data found in the literature is obtained.