The objective of this study is to understand the convective heat transfer of water-based nanofluid flowing through a vertical duct. The duct is filled with nanofluid saturated with porous medium sandwiched between permeable fluid. The two vertical walls of the enclosure are kept at constant temperature. The flow in the porous material is defined by Darcy equation. The Boussinesq approximation is invoked so that the effect of density variation is combined with the buoyancy forces. Separate solutions are matched at the interface using suitable matching conditions. Continuity of velocity, continuity of shear stress, continuity of temperature and continuity of heat flux are assumed at the interface. The equations of momentum and energy are coupled and nonlinear. Approximate analytical solutions are obtained using regular perturbation method. Results for a wide range of governing parameters such as Grashof number, Brinkman number, porous parameter, and solid volume fraction are plotted on the flow fields. It is found that the presence of porous matrix and solid volume fraction suppress the velocity and temperature fields where as Grashof number and Brinkman number promotes the flow. Numerical values for the skin friction and the Nusselt number at the left and right walls are also evaluated and are depicted in tabular form.
Nanofluids, Porous media, Mixed convection, Vertical duct
