Natural convection flow and heat transfer within a rectangular enclosure containing a vertical porous layer

An experimental and theoretical study of natural convection flow and heat transfer within a rectangular enclosure partially filled with an anisotropic porous medium is conducted as a step to understand the effects of the mushy region flow characteristics on the interacting flows of the melt pool and the mushy zone of solidifying alloys. The test cavity is filled with a porous medium for half the lateral distance to the cold wall and is heated and cooled at the vertical end walls by imposing uniform but different temperatures. The solid matrices of the porous media are constructed with perforated plates, and measured flow characteristics are used in the predictions. Flow visualization in the porous region is made possible by the latticed structure of the porous matrices and electrolysis dye generation. The effect of anisotropic flow characteristics of the porous medium on the flow and heat transfer is modeled mathematically using volume-averaged conservation equations. The mathematical model was validated by comparing the predicted velocity and temperature fields with the visualized streamlines and measured temperatures. To investigate the effect of anisotropic permeability for wider ranges of dimensionless parameters, numerical experiments were conducted. The importance of incorporating the mathematical models which account for the anisotropic characteristics of the mushy zone is emphasized.