Natural convection heat transfer from a bank of orthogonal heated plates embedded in a porous medium using LTNE model: A comparison between in-line and staggered arrangements

Abstract

This study numerically presents the characteristics of natural convection induced by a bank of orthogonal heated plates instilled inside porous cavity using the assumption of local thermal non-equilibrium (LTNE) and non-Darcian conditions. In-line and staggered arrangements of heated sections have been investigated for the purpose of comparison. Attention has been given on how the arrangement of heated sections affects the performance of heat transfer for various related parameters. Numerical solutions demonstrated that the average Nusselt number (Nu) is robustly depends on thermal conductivity ratio (Kr), inertia parameter (Fs/Pr*) and modified Rayleigh number (Ra*) in comparison with scaled heat transfer coefficient (H). The results show that the solid Nusselt number (Nus) is lower than fluid Nusselt number (Nuf) for same value of Fs/Pr* owing to Fs/Pr* is directly affected on the fluid phase. Although Kr has a considerable effect on all Nu in comparison with H, H has a substantial impact on the strength of LTNE zone as compared to Kr, particularly for smaller Kr and H. The medium inside the enclosure nearly reaches the equilibrium condition for larger values of H and Kr. Most importantly, the results indicated that the performance of in-line arrangement is better than that obtained with staggered ones. Therefore, in-line arrangement can be recommended to be employed in manufacturing flat heat exchangers for applications involving porous media under natural convection case.