EFFECTS OF VARIABLE TEMPERATURE ON MIXED CONVECTION OF A CU-WATER NANOFLUID IN A DOUBLE-LID-DRIVEN POROUS ENCLOSURE WITH ACTIVE MIDDLE VERTICALWALL

Abstract

This work is focused on the numerical modeling of laminar mixed convection in a double-lid-driven porous enclosure with sinusoidal heating on vertical walls, thermally insulated horizontal walls, and walls saturated with a Cu-water nanofluid. The dispersed nanoparticle-filled porous enclosure has a moving hot wall at the center. The generalized governing equations with the non-Darcy porous media model are solved numerically using the finite volume method. The present results are found to be in good agreement with the numerical results available in the open literature. The results of the fluid flow and heat transfer characteristics are reported for the Richardson number (Ri) from 0.01 to 100, Darcy number (Da) from 10(-3) to 10(-6), heat generation parameter (S) from 0 to 10, porosity (epsilon) of the porous medium from 0.2 to 0.9, solid volume fraction of nanoparticle (phi) from 0.0 to 0.2, and height-to-length aspect ratio (AR) from 1/3 to 3 for the fixed Prandtl number (Pr = 6.2). It is found that the presence of copper nanoparticles in the fluid-saturated porous media assures the enhancement in average Nusselt number value, and the existence of a moving vertical wall helps to maximize the overall heat transfer performance.