Augmentation of natural convection heat transfer in triangular shape solar collector by utilizing water based nanofluids having a corrugated bottom wall

Nanofluids have been introduced for the enhancement in the heat transfer phenomena in the last few years. In this paper a corrugated bottom triangular solar collector has been studied introducing water based nanofluids inside the enclosure. The corrugated bottom is kept at a constant high temperature whereas the side walls of the triangular enclosure are kept at a low temperature. Three types of nanoparticles are taken into consideration: Cu, Al2O3, and TiO2. The effect of solid volume fraction (phi) of the nanoparticle of nanofluid has been studied numerically by Galerkin weighted residual method of finite element for a wide range of Grashof number (Gr) 10(4)-10(6). Calculations are carried out for phi = 0, 0.05, 0.08, and 0.1 and dimensionless time, tau = 0.1, 0.5, and I. For the specified conditions streamlines and isotherm contours are obtained and detailed results of the interaction between different parameters are studied using overall Nusselt number. It has been found that both Grashof number and solid volume fraction have significant influence on streamlines and isotherms in the enclosure. It is also found that heat transfer increased by 24.28% from the heated surface as volume fraction phi increases from 0% to 10% at Gr = 10(6) and tau = 1 for copper water nanofluid. (C) 2013 Elsevier Ltd. All rights reserved.