Analysis of nanofluid heat transfer in parallel-plate vertical channels partially filled with porous medium

In this article, mixed-convective heat transfer of nanofluids in a vertical channel partially filled with highly porous medium was studied. In the porous region, the Brinkman–Forchheimer extended Darcy model was used to describe the fluid flow pattern. Different viscous dissipation models were also applied to account for viscous heating. At the porous medium–fluid interface, interfacial coupling conditions for the fluid velocity and temperature were used to derive the analytical solution using a two-parameter perturbation method. The model used for the nanofluids incorporates the effects of Brownian motion and thermophoresis. With constant wall temperature, velocity and temperature profiles and expressions for the Nusselt number values were obtained for fully-developed fluid flow. In addition, a numerical analysis was conducted using finite-difference method to compare the obtained results. Finally, a parametric study was conducted to investigate the influences of various parameters on the fluid flow pattern and heat-transfer performance. The predicted results clearly indicate that the presence of nanoparticles in the base fluid enhances the heat-transfer process significantly. ► We present an analysis of mixed-convective heat transfer of nanofluids. ► Brinkman–Forchheimer extended Darcy model is used to describe fluid flow pattern. ► Different viscous dissipation models are applied to account for viscous heating. ► We present an analytical approximate solution using a perturbation method. ► Effects of Brownian motion and thermophoresis are included.