Mixed Convection in a Cavity Saturated with Wavy Layer Porous Medium: Entropy Generation

摘要

In this paper, the effects of the wavy nanofluid/porous interface on the mixed convection and entropy generations of Cu-water nanofluid in a horizontally partitioned non-Darcy porous double lid-driven cavity are investigated. The bottom cavity wall is heated, and the top wall is cooled. Both of the left and right walls are adiabatic. The upper and the lower parts of the square cavity are filled with the nanofluid. The wavy middle part of the cavity is filled with the non-Darcy porous medium. The effects of the fundamental parameters were studied, including Reynolds number, Richardson parameter (Ri = 0.0001-100), and Darcy parameter (Da = 10(-6)-10(-2)) as well as nanofluid/porous interface parameters including the porous media height (H = 0.1-0.9), nanofluid heights, the amplitude of wavy interface (A = 0.05-0.3), and the number of interface undulations (n = 2-6). It is found that the decrease of the Darcy parameter brings a big resistance force for the fluid flow, an increase in the heat transfer by conduction, and a significant decrease in the irreversibility due to the heat transfer. And the effects of the nanoparticle concentrations depend on the convection mode. The average Bejan number is close to unity at forced convection mode.