Effect of concentric and eccentric porous layer on forced convection heat transfer and fluid flow around a solid cylinder.

In this paper, heat transfer and fluid flow around a solid cylinder wrapped with a porous layer in the channel were studied numerically by computational fluid dynamics (CFD). The homogeneous concentric and eccentric porous medium round a rigid, solid cylinder are supposed at local thermal equilibrium. The transport phenomena within the porous layer, volume averaged equations were employed, however the conservation laws of mass, momentum and energy were applied in the channel. The main purpose of this study is analyzed and compared the heat flux of concentric and eccentric porous layer in Reynolds number range of 1 to 40 and Darcy numbers of 10^-2 to 10^-6. It is found that with the decline of Darcy number, the vortex length is increased behind the solid cylinder surface. In addition, the heat flux rate of the cylinder is raised with the increase of Reynolds number. Finally, the results showed that the average Nusselt numbers in different Darcy and Reynolds numbers are higher in the eccentric porous layer than in the concentric porous layer. For example, our findings show that in Da=〖10^(-5), Re=40 and d=0.07 m, the average Nusselt number in the eccentric porous layer is 7.5% higher than the concentric porous layer.