Forced Convective Heat Transfer Enhancement in a Tube with its Core Partially Filled with a Porous Medium

Forced convection in a tube with its core partially filled with a porous medium is treated both analytically and numerically to find its high heat transfer performance. Assuming a fully developed flow subject to a constant heat flux, both friction factor and Nusselt number are presented explicitly as functions of the Reynolds number, Darcy number and porous core diameter ratio. Partial filling of the porous medium in the core region leads the fluid particles close to the wall, resulting an increase in the heat transfer coefficient. Extensive filling, however, tends to block the fluid particles channeling through the small gap formed between the wall and the porous core interface. Consequently, there exists the optimal porous core diameter ratio as a function of the Darcy number, which yields the maximum heat transfer coefficient.