RT Journal Article ID 77cfab913a65e555 A1 Aly, Abdelraheem M. A1 Raizah, Z. A. S. A1 Ahmed, Sameh Elsayed T1 NATURAL CONVECTION IN AN ENCLOSURE SATURATEDWITH MULTILAYER POROUS MEDIUM AND NANOFLUID OVER CIRCULAR CYLINDERS: ENTROPY GENERATION JF Journal of Porous Media JO JPM YR 2018 FD 2018-09-18 VO 21 IS 10 SP 1007 OP 1024 K1 entropy generation; non-Darcy flow; natural convection; nanofluid; circular cylinders AB The effect of the presence of circular cylinders on the natural convection in a horizontally partitioned non-Darcy porous enclosure filled with Cu-water nanofluid was investigated using the finite volume method. In this study, we used one domain approach based on the binary parameters to couple the governing equations for the nanofluid layer and the porous medium layers. The effects of the Rayleigh number, Darcy number, and porous layer height on the heat transfer of Cu-water nanofluid and entropy generations were investigated. The two different boundary conditions for the inner circular cylinders as isothermal and adiabatic boundaries were considered. The effects of the porous layer height (H = 0.1–0.9), solid volume fraction (φ = 0.0–0.04), Rayleigh number (Ra = 103–106), and Darcy number (Da = 10-5–10-2) were investigated. The current investigations showed that the presence of the circular cylinders with different boundary conditions strongly affect the strength of the stream function, convective heat transfer, and entropy generations. Adding nanoparticles in the partial porous enclosure including inner circular cylinders offered a slight increase in the average Nusselt number, the maximum values of the total entropy generation, and the average Bejan number. The current numerical results are well validated and have favorable comparisons with previously published results. PB Begell House LK https://www.dl.begellhouse.com/journals/49dcde6d4c0809db,7f1a4073667d2ab3,77cfab913a65e555.html