EFFECT OF AN INSERTED POROUS LAYER INTO A CHANNEL ON HEAT TRANSFER AND PRESSURE DROP

In this study, fully developed heat and fluid flows in a partially porous channel are investigated. The walls of the channel are subjected to equal heat fluxes. The porous layer is located in various positions in the channel. The motion and energy equations for clear and saturated porous layer are solved analytically and the temperature and velocity fields are obtained. The changes of the individual Nusselt number of both walls with different values of Darcy number and porous layer locations are analyzed. Three dimensionless parameters-heat transfer increment ratio, the pressure drop increment ratio, and overall performance, which shows the changes of heat transfer and pressure drop by inserting a porous layer in a fully developed clear channel-are defined and calculated. The study is performed for thermal conductivity ratio and porous layer thickness of unity. The obtained results show that maximum overall performance (maximum heat transfer enhancement with minimum increase of pressure drop) for a channel by inserting a porous layer can be obtained when the porous layer is located at the center or in the region very close to the lateral surfaces.