Buoyancy-Driven Flow in Saturated Porous Media

Buoyancy-driven convection on a vertical, constant heat flux surface that bounds a fluid-saturated porous medium is experimentally studied with a primary focus on developing steady-state heat transfer correlations for porous media comprising different particulate solid with water being the interstitial fluid. Results show that heat transfer coefficients can be adequately determined via a Darcy-based model, and our results confirm a correlation proposed by Bejan [1]. It is speculated that the reason that the Darcy model works well in the present case is that the porous medium has a lower effective Prandtl number near the wall than in the bulk medium. The factors that contribute to this effects include the thinning of the boundary layer near the wall and an increase of effective thermal conductivity.