Numerical investigations of convection heat transfer in a thermal source-embedded porous medium via a lattice Boltzmann method

Abstract

Convection heat transfer (CHT) in porous media founds broad significance in the applications of solar collectors, geothermal systems, and biological sciences. In this work, the natural CHT in a porous medium embedded with a rectangular thermal source at the bottom is numerically solved via the lattice Boltzmann method (LBM). The generalized Brinkman-Forchheimer-extended-Darcy model is applied to describe the momentum equation. The numerical solutions obtained by the LBM are verified against the experimental data for the correctness validation of the presented lattice Boltzmann model. Effects of the Darcy number (Da), medium porosity (ε), size of the thermal source, and the aspect ratio of the thermal source on the temperature- and flow-field in the porous medium are systematically investigated. Results show that the increase of Da remarkably enhances the heat exchange and changes the heat transfer mode from conduction to convection. The existence of the thermal source sidewall has a suppression effect on the heat exchange along the top wall of the thermal source, and this suppression effect is pronounced when the CHT is weak.

Keywords

• Convection heat transfer
• Porous medium
• Embedded thermal source
• Lattice Boltzmann simulation