MHD natural convection of hybrid nanofluid in an open wavy cavity

Abstract

In this paper, natural convection heat transfer of Al2O3-Cu/water hybrid nanofluid within open wavy cavity and subjected to a uniform magnetic field is examined by adopting the lattice Boltzmann method scheme. The left wavy wall is heated sinusoidal, while the right wall is open and maintained to the ambient conditions. The top and the bottom horizontal walls are smooth and insulated against heat and mass. The influence of solid volume fraction of nanoparticles (φ = 0, 0.02, 0.04), Rayleigh number (Ra = 103, 104, 105), Hartmann number (Ha = 0, 30, 60, 90) and phase deviation (Φ = 0, π/4, π/2, 3π/4) are investigated on flow and heat transfer fields. The results proved that the Nusselt number decreases with the increase of the Hartmann number, but it increases by the increment of Rayleigh number and nanoparticle volume fraction. The magnetic field rises or falls the effect produced by the presence of nanoparticles with respect to Rayleigh number. At Ra = 103, the effect of the raising phase deviation on heat transfer is erratic while it has a positive role in the improvement of nanoparticles effect at Ra = 105. Keywords: Hybrid nanofluid, Lattice Boltzmann method, Magnetic field, Open cavity, Sinusoidal temperature distribution, Wavy enclosure