Abstract
Heat transfer and fluid flow in a square cavity with partially heated side walls filled with nanofluid has been studied numerically using different types of nanoparticles. A two heat sources maintained at a constant heat flux q '' are embedded in the right and the left wall. The enclosure was cooled from the top and bottom walls. The remaining boundary parts are kept insulated. Method of solution is based on the finite volume method and an accelerated multigrid which has been tested and compared with previously published work on the basis of special cases and proved excellent agreements. The influence of pertinent parameters such as Rayleigh number, the type of nanofluid, the solid volume fraction of nanoparticles and the location of the heat sources on the heat transfer and fluid flow is studied. Different configurations corresponding to the sources locations are investigated. Results were presented by streamlines, isotherms, average and local Nusselt numbers for Rayleigh number in the range (10(4) <= Ra <= 10(7)), solid volume fraction of nanoparticles in the range (0 <= phi <= 0.2) and different types of nanoparticles (Cu, Ag, Al2O3 and TiO2). It was found that the heat transfer increases with increasing of Rayleigh number and volume fraction of nanoparticles. In addition, the maximum source temperature has been significantly affected when their locations are considered. Regardless the Rayleigh number and the solid volume fraction of nanoparticles, the highest heat transfer enhancement occurs for the down-top case, while the minimum is reached in the middle-middle case. Multiple correlations in terms of the Rayleigh numbers and the solid volume fraction of nanoparticles have been established. (C) 2012 Elsevier Ltd. All rights reserved.