Free convection in a square cavity filled by a porous medium saturated by a nanofluid: Viscous dissipation and radiation effects

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• 作者：M. Ghalambaz^a ; ^{m.ghalambaz@iaud.ac.ir" class="auth_mail" title="E-mail the corresponding author} ; M. Sabour^a ; I. Pop^b
• 关键词：Viscous dissipation ; Radiation effects ; Nanofluid ; Porous media
• 刊名：Engineering Science and Technology,an International Journal
• 出版年：2016
• 出版时间：September 2016
• 年：2016
• 卷：19
• 期：3
• 页码：1244-1253
• 全文大小：3867 K

文摘

The influence of the viscous dissipation and radiation effects on the natural convection heat transfer in a square cavity filled with porous media saturated with a nanofluid is studied. The vertical walls of the cavity are subject to finite temperature difference while the top and bottom walls of the cavity are insulated. The Buongiorno's nanofluid model, incorporating the Brownian motion and thermophoresis effects, is employed. The governing equations, in nondimensional form, are written in the weak form and solved using the finite element method. The influences of viscous dissipation and radiation effects on the concentration distribution of nanoparticles are discussed. The average and local Nusselt numbers are reported for various values of viscous dissipation (Eckert number) and radiation effects. The results show that the Nusselt numbers at the hot and cold walls are not equal due to the presence of viscous dissipation effects. The raise of Eckert number decreases the Nusselt number at hot wall, but it increases the Nusselt number at the cold wall. It is also found that the increase of Lewis number enhances the heat transfer in the cavity.