Ghalambaz Mohammad, Sheremet Mikhail A, Pop Ioan
Department of Mechanical Engineering, Dezful Branch, Islamic Azad University, Dezful, Iran.
Department of Theoretical Mechanics, Faculty of Mechanics and Mathematics, Tomsk State University, Tomsk, Russia; Institute of Power Engineering, Tomsk Polytechnic University, Tomsk, Russia.
PLoS One. 2015 May 19;10(5):e0126486. doi: 10.1371/journal.pone.0126486. eCollection 2015.
The free convection heat transfer of Cu-water nanofluids in a parallelogrammic enclosure filled with porous media is numerically analyzed. The bottom and top of the enclosure are insulated while the sidewalls are subject to limited temperature difference. The Darcy flow and the Tiwari and Das' nanofluid models are considered. The governing dimensionless partial differential equations are numerically solved using a finite difference code. The results are reported for isotherms and streamlines as well as Nusselt number as a function of the volume fraction of nanoparticles, porosity, types of the porous matrix, inclination angle, aspect ratio and different Rayleigh numbers. It is found that the presence of the nanoparticles inside the enclosure deteriorates the heat transfer rate, which is caused due to the increase of dynamic viscosity by the presence of nanoparticles. Therefore, in applications in which the nanofluids are used for their advantages, such as enhanced dielectric properties or antibacterial properties, more caution for the heat transfer design of the enclosure is necessary.
对充满多孔介质的平行四边形封闭腔内铜水纳米流体的自由对流换热进行了数值分析。封闭腔的底部和顶部隔热，而侧壁存在有限温差。考虑了达西流以及蒂瓦里和达斯的纳米流体模型。使用有限差分代码对控制无量纲偏微分方程进行数值求解。报告了等温线、流线以及努塞尔数随纳米颗粒体积分数、孔隙率、多孔基质类型、倾斜角、纵横比和不同瑞利数的变化结果。研究发现，封闭腔内纳米颗粒的存在会降低传热速率，这是由于纳米颗粒的存在导致动力粘度增加所致。因此，在利用纳米流体优势（如增强介电性能或抗菌性能）的应用中，对封闭腔的传热设计需要更加谨慎。
