Natural convection of a nanofluid inside a vertical circular enclosure exposed to a non-uniform heat flux

• Published in: International communications in heat and mass transfer Vol. 76; pp. 337 - 347
• Main Authors: Habibi Matin, Meisam, Vaziri, Shadi
• Format: Journal Article
• Language: English
• Published: Elsevier Ltd 01.08.2016
• Subjects: Circular enclosure; Circularity; Enclosure; Flux; Heat flux; Heat transfer; Mathematical analysis; Nanofluid; Nanostructure; Natural convection; Three dimensional; Walls; Natural convection; Circular enclosure; Nanofluid; Heat flux; Three dimensional
• ISSN: 0735-1933; 1879-0178
• DOI: 10.1016/j.icheatmasstransfer.2016.06.008

In the present study natural convection of Al2O3-water nanofluid inside a vertical circular enclosure is investigated. The enclosure is exposed to heat flux with a non-uniform distribution from the bottom. The objective is finding the heat flux distribution for which the heat transfer coefficient is optimum at different values of the governing parameters. For examining the effect of heat flux distribution on thermal transport phenomenon, 9 various flux distributions are considered as cases 1 to 9. The bottom side of the enclosure is divided to six annular strips each of which receives a portion of the total heat i.e., the flux applied on each strip is different. The side wall is kept at constant temperature and the top wall is assumed to be adiabatic. A numerical finite volume scheme is employed to solve non-dimensional conservative equations in cylindrical coordinates. In addition to the heat flux distribution, the effects of Rayleigh number (104<Ra<106), nanoparticles volume fraction (φ<0.08) and aspect ratio (Γ=0.5, 1 and 1.5) on isotherms and Nusselt number are analyzed. It is observed that there are physical conditions for which the heat transfer characteristic is optimized.