Two-phase modeling of the free convection of nanofluid inside the inclined porous semi-annulus enclosure

• Published in: International journal of mechanical sciences 2019-12, Vol.164, p.105183, Article 105183
• Main Authors: Motlagh, Saber Yekani, Golab, Ehsan, Sadr, Arsalan Nasiri
• Format: Article
• Language: English
• Subjects: Buongiorno model; Half-annulus enclosure; Magnetic nanofluid; Natural Convection; Porous Medium
• ISSN: 0020-7403; 1879-2162
• DOI: 10.1016/j.ijmecsci.2019.105183

•Two-phase free convection of Fe3O4-water nanofluid inside the inclined semi-annulus porous enclosure is investigated and Buongiorno's model is used for considering the effect of nanoparticles diffusion.•Effects of porous Rayleigh number, inclination angle of enclosure, volume fraction of nanoparticles and porosity number on the flow pattern, temperature field, nanoparticle distribution and Nusselt number are investigated.•The distribution of nanoparticles on the external cylinder wall with constant temperature boundary conditions is more than the constant flux internal cylinder due to the effect of thermophoresis.•Distribution of nanoparticles in high porous Rayleigh number is more uniform than low porous Rayleigh number. In the present paper, the modeling of the free convection of two-phase nanofluid inside the inclined porous semi-annulus enclosure is considered. The cavity is filled with Fe3O4-water magnetic nanofluid. Buongiorno and Darcy models are used for modeling two-phase and porous media, respectively. The governing equations are discretized by finite volume method and SIMPLE algorithm. The effect of parameters such as inclination angle of cavity (0 ≤ θ ≤ 90), porous Rayleigh number (10 ≤ Rap ≤ 103), porosity number (ε = 0.4 and 0.7), and volume fraction of nanoparticles (0 ≤ φAve ≤ 0.04) on the flow pattern, temperature field, nanoparticle distribution, and Nusselt number are studied. In low porous Rayleigh numbers, Nusselt number is not the function of porosity number and the inclination angle of the enclosure. Also, Nusselt number increases by adding the volume fraction of nanoparticles. However, in high porous Rayleigh numbers, the heat transfer rate is reduced by increasing the inclination angle of the enclosure. Furthermore, with the increase in the porosity number, Nusselt number is increased.