Numerical Investigation of Mixed Convection and Entropy Generation in a Wavy-Walled Cavity Filled with Nanofluid and Involving a Rotating Cylinder

摘要

This numerical study considers the mixed convection and the inherent entropy generated in Al2O3–water nanofluid filling a cavity containing a rotating conductive cylinder. The vertical walls of the cavity are wavy and are cooled isothermally. The horizontal walls are thermally insulated, except for a heat source segment located at the bottom wall. The dimensionless governing equations subject to the selected boundary conditions are solved numerically using the Galerkin finite-element method. The study is accomplished by inspecting different ranges of the physical and geometrical parameters, namely, the Rayleigh number (103≤Ra≤106), angular rotational velocity (0≤Ω≤750), number of undulations (0≤N≤4), volume fraction of Al2O3 nanoparticles (0≤ϕ≤0.04), and the length of the heat source (0.2≤H≤0.8). The results show that the rotation of the cylinder boosts the rate of heat exchange when the Rayleigh number is less than 5×105. The number of undulations affects the average Nusselt number for a still cylinder. The rate of heat exchange increases with the volume fraction of the Al2O3 nanoparticles and the length of the heater segment.