Analysis of Natural Convection in a Nanofluid-Filled Open Cavity with a Sinusoidal Boundary Condition in the Presence of a Magnetic Field

This paper examines natural convection in an open cavity with a sinusoidal thermal boundary condition. The cavity is filled with a water-Al2O3 nanofluid and subjected to a magnetic field. The Lattice Boltzmann method (LBM) is applied to solve the coupled equations of flow and temperature. The study has been carried out considering parameters in the following ranges: Rayleigh number of the base fluid, Ra = 103 to 106, Hartmann number varied from Ha = 0 to 60, phase deviation γ = 0, π4, π2, 3 π4 and π and solid volume fraction of nanoparticles between π = 0 and 6%. Results show that the heat transfer rate decreases with the Hartmann number and increases with Rayleigh number. At Ha = 30 and Ra = 103 - 105, for all phase deviations the addition of nanoparticles increases the heat transfer rate. Also, at low Rayleigh number (Ra ≤ 104) the highest heat transfer rate is obtained for γ = π2.