A numerical study of the natural convection of Al2O3-EG nanofluid in a square enclosure and impacts and a comparison of various viscosity and thermal conductivity models

Abstract

In the current study, heat transfer enhancement in an enclosure was investigated by utilizing Al2O3-EG nanofluid. In the numerical solutions, the solid-liquid mixture equations were applied for the enclosure that composed alumina-ethylene glycol nanofluid, in terms of the two-dimensional buoyancy-driven convection. Various viscosity and thermal conductivity models were utilized for the purpose of assessing heat transfer improvement. The purpose of this study was to reveal the impacts caused by uncertainties in the viscosity and thermal conductivity of the nanofluid on laminar natural convection heat transfer occurring in a square enclosure. The temperatures of the right and left vertical walls of the enclosure were kept constant as Tc and Th, respectively, whereas the thermal insulation of the other walls was performed. The discretization of the governing equations was performed by utilizing the finite volume method and the SIMPLE algorithm. Calculations were made for the Rayleigh number (10 3 -10 6 ) and the volume fraction of alumina nanoparticles, ϕ= 0-5%. In this study, many parameters affecting heat transfer by natural convection were investigated in the enclosure containing Al2O3-EG nanofluid, and it was found that nanofluid viscosity was the most efficient factor for heat transfer rate.