Mixed convection and heat flow characteristics in a lid-driven enclosure with porous fins: Full numerical modeling and parametric investigations

Abstract

The effects of porous fins on mixed convection inside lid-driven square enclosures were reported in the present work. The porous medium with varying permeability, instead of the solid one, could widely change the baffling performance on the fluid flow, where this characteristic could be beneficial for controlling fluid flow and energy transport, typically electronic cooling process. The top lid could have the two-way movement. The working fluid in the cavity was governed by the N-S equations while that within porous medium was determined by the non-Darcy model called the Darcy-Forchheimer model based on representative element-averaging method. Relevant governing parameters, including Richardson number, Darcy number, quantities, length and distribution ratio of porous fins, are sensitively varied to identify their effects and roles on mixed convection heat transfer. Numerical results illustrate that the mechanism of main circulation development is modified by the additional fins. The adding porous fins with excellent permeability enhance heat transfer dramatically, while these fins with tiny Darcy number deteriorate heat transfer rate. The rate of heat transfer enhancement due to the increasing of the length and quantities of fins decreases. Furthermore, the distribution ratio shows the significant effects on the fluid flow and heat transfer. Present investigations could benefit the microelectronic cooling through the installation of porous-alike materials or modules.