Numerical Investigation of Nanofluid Mixed-Convection Flow in the Entrance Region of a Vertical Channel Partially Filled with Porous Medium

摘要

In this article, transient two-dimensional mixed convection of nanofluids in the entrance region of a vertical channel has been studied carefully. The geometry under consideration consisted of a parallel-plate channel partly filled with a porous medium with a constant wall temperature. In the free flow region, the two-dimensional flow field has been governed by the Navier-Stokes equations. The general formulation of the momentum equations accounting for the inertial and the viscous effects in the presence of a porous medium has been used. Viscous dissipation effects have also been incorporated in the thermal energy equation. Effects of Brownian diffusion and thermophoresis have also been included for nanoparticles in the nanofluid. The governing equations have been given in terms of the stream function-vorticity formulation and have been non-dimensionalized and then solved numerically subject to appropriate boundary conditions. The characteristics of the flow and temperature fields have been presented in the terms of mixed-convection parameter (GR), Brinkman number (Br), Darcy number (Da), Lewis number (Le), and other important parameters.