Lattice Boltzmann Simulation of Magnethydrodynamics Natural Convection in an L-Shaped Enclosure

This paper presents the results of a numerical study on the natural convection of Al2O3-H2O nanofluid in an L-shaped cavity in the presence of a uniform magnetic field. The Lattice Boltzmann Method (LBM) is used to solve the governing equations. The effective thermal conductivity and viscosity of nanofluid are calculated by KKL(Koo-Kleinstreuer-Li) correlation. The influence of pertinent parameters such as Rayleigh number (10(4)<= Ra <= 10(6)), Hartmann number (0 <= Ha <= 60),nanoparticle volume concentration (0 <=phi <= 0.04) and the cavity aspect ratio (0.2 <= AR <= 0.5) on the flow and heat transfer characteristics have been examined. The heat transfer increases first, then considering the role of Brownian motion of nanoparticles and increases with increasing of volume fraction of nanoparticles. But, on the contrary, Hartmann number and aspect ratio of the cavity have others important improvement factor for decreasing free convection in the enclosures.