Flow and heat transfer simulation in a wall-driven porous cavity with internal heat source by multiple-relaxation time lattice Boltzmann method (MRT-LBM)

Abstract

Laminar mixed convection characteristics in a wall driven porous cavity with an isothermally heated square blockage inside have been investigated numerically by the Non-orthogonal multiple-relaxation time lattice Boltzmann method (MRT-LBM). Various directions of wall driven and placement of the blockage have been considered. In the current study, the geometrical and flow parameters being investigated are the directions of wall driven, blockage position (ex, ey), the Richardson number (Ri). From the analysis of the mixed convection process with different directions of wall driven, the results show that under the configuration of central placement of the blockage, the most preferable heat transfer is obtained in the right wall driven at any values of the Richardson number. Because the movement of the wall can lead to an assisting effect on the buoyancy flow in the right wall driven. Since the right wall driven has the best heat transfer effects, the influences of blockage location and Richardson number is investigated in this condition. When the value of the Richardson number is 0.1, the most preferable heat transfer is obtained when the blockage is placed at the top right and bottom right. When the value of the Richardson number is 1.0 or 10.0, both the middle left and middle right blockage placement have the best heat transfer rate. That is mainly due to the influence of the size, strength and position of the vortex, the combined effect of forced convection and natural convection is stronger when the blockage is placed at those locations.