Natural convection of Nanoliquid from a Cylinder in Square Porous Enclosure using Buongiorno's Two-phase Model

Sci Rep. 2020 Jan 10;10(1):143. doi: 10.1038/s41598-019-57062-x.


Natural convection of nanoliquid in a square porous enclosure has been studied using non homogeneous two-phase Buongiorno's model. The outer of enclosure has cold temperature and a circular cylinder is put at the center. A finite heated segment is located on the top cylinder surface which is otherwise insulated. The momentum in the porous layer is modeled applying the Brinkman-Forchheimer equations. The analysis are conducted in the following interval of the associated groups: the portion of heated surface (5% ≤ H ≤ 100%), the concentration (0.0 ≤ ϕ ≤ 0.04), the Darcy number, 10-5 ≤ Da ≤ 10-2 and the cylinder size, (0.15 ≤ R ≤ 0.25). The minimum heat transfer rate of the active surface were obtained at location ξ = 90°. In general, the ratio of the heat transfer per unit area of the heat source decreases as the length of the heated surface increases. The heat transfer rate is intensified for the half thermally active surface and high value of Darcy number at higher nanoparticles concentration.