... material. It is reasoned that this is due to the thinning of the momentum boundary layers as a result of the presence of the porous material, which acts as a momentum sink. As a result of the thinner boundary layers, the flow speed near the finned surfaces and base is increased, which serves to increase...

... shaped enclosure. A composite model is developed based on asymptotic solutions for three limiting cases: pure conduction, laminar boundary layer convection, and transition flow convection. The conduction shape factor and natural convection models are validated using data from CFD simulations for a wide...

.... The optimal aspect ratio for ducts with forced and natural convection corresponds to the special geometry and flow conditions where boundary layers meet just as the coolant exits the channel. This “constructal” design principle is illustrated by several classes of examples: laminar forced and natural...

... enhanced when fins are incorporated in metal foam. The heat transfer coefficient increases with increase in the number of fins until adding more fins retards heat transfer due to interference of thermal boundary layers. For the 20 PPI samples, this maximum was reached for four fins. For the 5 PPI heat...

..., as shown in Eq. ( 1 ), namely the diffusive limit or the conduction shape factor of the cuboid given in Eq. ( 4 ) and the Nusselt number for boundary layer forced convection (spheroid model, Eq. ( 6 ), equivalent flat plate model, Eq. ( 24 ) and the cuboid model, Eq. ( 19 )). A blending parameter of n...