Forced Convection Heat Transfer From a Bank of Circular Cylinders Embedded in a Porous Medium

Abstract

The characteristics of fluid flow and forced convection heat transfer around a bank of four circular cylinders embedded in a metallic or non-metallic porous materials have been investigated numerically. Both a staggered and an in-line arrangement have been studied. The governing continuity, Darcy–Brinkman–Forchheimer momentum, and local thermal non-equilibrium energy equations are solved by the spectral-element method. Attention is focused on how the spacing parameter SP ∈ [1.5, 3.0] (the space between cylinder centers) affects the local and average heat transfer from the cylinders at three different solid-to-fluid thermal conductivity ratios kr = 1.725, 57.5, 248, and at different Reynolds numbers ReD ∈ [1, 250] in both arrangements. Perhaps not surprisingly, the results show that both the average Nusselt number, Nuf, and the local Nusselt number, Nufφ, are dependent strongly on ReD, SP, and the cylinder arrangement. However, it is found that the trend of the variations of Nuf with SP is not considerably altered by kr in both cylinders’ configurations. The results also show that the thermal performance of the staggered arrangement is higher than that for the in-line one, with less occupied space; therefore, it is practically and economically recommended that this arrangement to be used in manufacturing tubular heat exchangers for applications involving porous media.