Slip Flow and Heat Transfer of Magnetic Fluids in Micro Porous Media Using a Lattice Boltzmann Method

Abstract

In this paper, a Lattice Boltzmann method was used to simulate the flow of temperature-sensitive magnetic fluids in a micro porous cavity. According to Navier’s linear slip length model, slip boundary conditions were used on all the walls of the micro porous cavity. The effects of the horizontal slip length and the vertical slip length on the flow and heat transfer characteristics were investigated. The results showed that with the increase of the slip length, the velocities and their gradients became smaller, so the convection was harder to occur, and the temperature was more stable. On the walls, the effects of the slip lengths on the Nusselt numbers at the edges and at the centers were different, so the local heat transfer efficiencies were changed accordingly. It was also found that when the horizontal slip length was set to be zero, the flow developed from one vertex to two vortexes along the vertical direction with the increase of vertical slip length. The corresponding critical vertical slip length first increased and then decreased with the Rayleigh number and the magnetic Rayleigh number.