Browsing by Author "MAACHE Mouna Battira, Samir Arrouf, Rachid Bessaih, Abdelmadjid Chehhat"

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    EFFECTS OF MAGNETIC FIELD DIRECTION AND NANOPARTICLES CONCENTRATION ON FREE CONVECTION IN A VERTICAL CYLINDER
    (2019-12-17) MAACHE Mouna Battira, Samir Arrouf, Rachid Bessaih, Abdelmadjid Chehhat
    In this work, the effect of the magnetic field direction on laminar stationary convection heat transfer in a vertical cylinder filled with a CuO nanofluid is numerically studied. The magnetic field externally applied to the cylinder is once directed axially (Bz) and a second time directed radially (Br). The cylinder having an aspect ratio( H)⁄(R_0=3), is limited by two upper and lower walls at constant temperatures respectively cold Tc and hot Th and by an adiabatic sidewall. The equations of continuity, Navier Stocks 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 the direction and intensity of the magnetic field on the dynamic field, on the thermal field and on the average Nusselt number are presented and discussed through the variation of the Hartmann number (Ha=0,5,10,15,20,30….60), as well as the effect of the nanoparticles volume fraction (∅=0,0.025,0.05,0.075,0.1) and this for three values of Rayleigh number ( Ra=10^3,5×10^3 and 10^4 ). The results found show that the average Nusselt number increases with the increase in the Rayleigh number but it decreases with the increase in the Hartmann number. Depending on the magnetic field direction and on the values of Hartmann and Rayleigh numbers, an increase in the volume fraction of the nanoparticles in the nanofluid may cause an enhancement or deterioration in the heat transfer performance in the nanofluid.