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Magnetohydrodynamic free convection and entropy generation in a square porous cavity. (English) Zbl 1079.76643
Summary: The problem of entropy generation in a fluid saturated porous cavity for laminar magnetohydrodynamic natural convection heat transfer is analyzed in this paper. Heat transfer results are also presented additionally. Darcy’s law for porous media is considered. Magnetic force is assumed acting along the direction of the gravity force. As boundary conditions of the cavity, two vertical opposite walls are kept at constant but different temperatures and the remaining two walls are kept thermally insulated. For a range of Rayleigh number ($Ra=1-{10}^{4}$) and Hartmann number ($Ha=0-10$), heat transfer, overall entropy generation rate, and heat transfer irreversibility are presented in terms of dimensionless Nusselt number ($Nu$), entropy generation number ($Ns$), and Bejan number ($Be$), respectively. Finally, parametric results are presented in terms of isothermal lines, streamlines, isentropic lines, and iso-Bejan lines.
##### MSC:
 76R10 Free convection (fluid mechanics) 76W05 Magnetohydrodynamics and electrohydrodynamics 76S05 Flows in porous media; filtration; seepage 80A20 Heat and mass transfer, heat flow