NATURAL CONVECTIVE FLOW IN CIRCULAR AND ARC CAVITIES FILLED WITH WATER-CU NANOFLUID: A COMPARATIVE STUDY

The fluid flow and heat transfer mechanism on steady state solutions obtained in circular and arc-square enclosures filled with water/Cu nanofluid as well as base fluid has been investigated numerically by Galerkin's weighted residual finite element procedure. The left and right boundaries of the cavities are, respectively, heated and cooled at constant temperatures, while their horizontal walls are adiabatic. Effects of buoyancy force (Rayleigh number) and viscous force (Prandtl number) with a wide range of Ra (10(3) - 10(6)) and Pr (4.2 - 6.2) on heat transfer phenomenon inside both cavities are observed. The solid volume fraction of water/Cu nanofluid is kept fixed as 2%. The fluid flow and temperature gradient are shown by streamlines and isotherms patterns. From the investigation, it has been reported that the Rayleigh and Prandtl numbers play significant role in heat transfer rate. The variation in heat transfer has been calculated in terms of average Nusselt number. Heat transfer rate has been found to be higher for water/Cu nanofluid with 2% solid volume fraction than pure water. About 2.7% higher heat transfer rate has been obtained for circular cavity than that of arc cavity using water/Cu nanofluid at Ra = 10(4) and Pr = 5.8. Better performance of heat transfer mechanism has been observed for circular cavity than arc cavity. It is concluded that using water/Cu nanofluid is advantageous for obtaining higher rate of heat transfer.