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

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 theenclosure that composed alumina-ethylene glycol nanofluid, in terms of the two-dimensionalbuoyancy-driven convection. Various viscosity and thermal conductivity models were utilized forthe purpose of assessing heat transfer improvement. The purpose of this study was to reveal theimpacts caused by uncertainties in the viscosity and thermal conductivity of the nanofluid onlaminar natural convection heat transfer occurring in a square enclosure. The temperatures of theright and left vertical walls of the enclosure were kept constant as Tc and Th, respectively, whereasthe thermal insulation of the other walls was performed. The discretization of the governingequations was performed by utilizing the finite volume method and the SIMPLE algorithm.Calculations were made for the Rayleigh number (103-106) and the volume fraction of aluminananoparticles, ?= 0-5%. In this study, many parameters affecting heat transfer by naturalconvection were investigated in the enclosure containing Al2O3-EG nanofluid, and it was foundthat nanofluid viscosity was the most efficient factor for heat transfer rate.