Enhancement of laminar natural convective heat transfer in concentric annuli with radial fins using nanofluids

In the present study, laminar natural convection of nanofluids confined between two horizontal concentric cylinders with eight radial fins attached to the inner cylinder is studied. Governing equations are solved using the finite volume method. The computations are performed for various Rayleigh numbers, nanofluids and volume fractions of nanoparticles. From the results, it is found that the average Nusselt number enhances when volume fraction and thermal conductivity of nanoparticles increases. Also, it is observed that the average Nusselt number of Cu-water nanofluid is highest among the nanofluids of the present study. Moreover, it is seen that the temperature gradient and absolute value of stream function decrease by addition of nanoparticles.