Numerical simulation of heat transfer enhancement of a solid cylinder wrapped with a porous layer

In the present study flow-field and temperature-field around a cylinder wrapped with a porous layer are investigated numerically. Effects of several parameters, such as porous layer thickness e_p and permeability Da as well as Reynolds number on flow-field and heat transfer characteristics are examined. The numerical results indicate that the presence of a porous layer has a strong effect on the heat transfer enhancement around the cylinder. The heat transfer is about 2.8~5.4 times enhanced compared to that around a cylinder without a porous layer. The wall averaged Nusselt number increased when e_p or Re increased, and decreased with Da increased. The drag coefficient Cd increased with the increase of e_p, but it increased as the speed increased initially and decreased afterwards, then it remains unchanged when Da<1×10^-5.