Génération d’entropie due au refroidissement par convection naturelle d’un nanofluide

Abstract

We present in this thesis a study of laminar natural convection and entropy generation in a square cavity filled with a nanofluid. The two vertical walls of the cavity are maintained at hot and cold temperatures, and the horizontal walls are thermally insulated. The governing equations of the phenomenon in question are solved by the finite volume method. A FORTRAN computer code has been developed to calculate the flow and thermal fields, average and local Nusselt numbers, and entropy generation. Effects of Rayleigh number, solid volume fraction of nanoparticles, length of the heat source, type of nanofluids, conductor (fin), its position and thermal conductivity, and thickness of the bottom wall of the cavity, on the flow and thermal fields, and on average Nusselt number, entropy generation and Bejan number are presented. Results show that the heat transfer by natural convection is more important in a nanofluid than in the basic fluid (water), but the entropy generation is less important. Finally, an experimental study of natural laminar convection in a cubic cavity filled with pure water is presented.