Natural Convection of Cu-water Nanofluid in Concentric Annuli with Six Radial Fins Attached to Inner

Laminar natural convection of Cu-water nanofluid between two horizontal concentric cylinders with radial fins attached to the inner cylinder has been studied numerically. The inner and outer cylinders are considered at constant temperature Ti and To respectively, with Ti>To. The governing equations with the corresponding boundary conditions have been solved by using the finite volume method. The hybrid-scheme has been used to discretize the convection terms. In order to couple the velocity field and the pressure in the momentum equations, the SIMPLER-algorithm has been adopted. The effects of variation of the Rayleigh number, the fins length and the volume fraction of nanoparticles on the fluid flow and heat transfer inside the annuli have been investigated. It is observed from the results, by increasing fins length, average Nusselt number decreases and heat transfer rate increases. Also, by increasing the volume fraction of nanoparticles, average Nusselt number and heat transfer rate increases.