Effects of Prandtl number on the forced convection heat transfer from a porous square cylinder

Abstract

Combined influence of Prandtl number and Darcy number variations on heat transfer from a two-dimensional porous square cylinder, placed in an unconfined computational domain, is investigated numerically for Pr=0.71–100. The porous cylinder is subjected to a steady cross-flow regime with Reynolds number and Darcy number varying between Re=1–40 and Da=10-6-10-2. Numerical simulations are carried out by modifying the generic buoyantBoussinesqPimpleFoam solver of OpenFOAM 5.0 coupled with Darcy-Brinkman-Forchheimer model, with single domain approach. Significant augmentation in heat transfer rate from the porous cylinder is reported by varying Pr,Re and Da. Detailed insight on the mechanism behind this thermal enhancement is provided through isotherm contours, temperature profiles and local, surface averaged and mean Nusselt number plots. A brief description on the relation between jump phenomenon that occurs in flow characteristics for porous square cylinder and heat transfer results is also given. An insight on the inclusion of Forchheimer source term in the steady flow regime is provided. Finally, correlations are provided for the mean Nusselt number for a few values of Pr and Da in terms of Re. Optimistically, scholars and engineers working on heat transfer increment through usage of porous material or intending to numerically model porous media theory will benefit from the information presented in this article. © 2018 Elsevier Ltd