Lattice Boltzmann simulation of natural convection in an open enclosure subjugated to water/copper nanofluid

In this paper Lattice Boltzmann simulation of natural convection in an open enclosure which subjugated to water/copper nanofluid has been investigated. Calculations were performed for Rayleigh numbers (Ra = 10(4)-10(6)), volume fractions of nanoparticles (0 <= phi <= 0.05) and open enclosure aspect ratios (0.5 <= A <= 2). The comparisons show that the average Nusselt number increases with augmentation of Rayleigh number and the volume fraction of nanoparticles for whole ranges of aspect ratios. The average Nusselt number decreases as the aspect ratio increases at various Rayleigh numbers and different the nanoparticle volume fractions. But generally the most effect of nanoparticles on heat transfer enhancement is observed at the aspect ratio of A=2. Also nanoparticles influence the heat transfer less at Ra = 10(5) among studied Rayleigh numbers. (C) 2011 Elsevier Masson SAS. All rights reserved.