Analysis of heat transfer and pumping power for bottom-heated porous cavity saturated with Cu-water nanofluid

The heat transfer and pumping power of a porous cavity along with nanofluid as working fluid is an important issue from the design and performance analysis as well as the operation point of view. Sometimes, for a thermo-fluid flow device, the major energy expenses may generate from pumping power of the flow supplying unit. In this work, the analysis of pumping power as well as heat transfer of a typical system is demonstrated considering bottom-heating, porous medium and Cu-water nanofluid. The nanofluid is injected into a bottom-heated porous cavity from the middle of top adiabatic wall and is vented out through the middle of cold sidewalls. Flow physics is governed by the nonlinear and coupled transport equations. These equations are modeled by the Brinkman-Forchheimer-extended Darcy model (BFDM) and solved by an indigenous CFD code. On the fluid flow and heat transfer process, the impact of various pertinent parameters like Reynolds number (Re = 10-200), Richardson number (Ri = 0.1-20), Darcy number (Da =10(-7)-10(-4)), porosity (epsilon = 0.1-1), nanoparticle volume fraction (phi = 1-5%) and cavity aspect ratio (A = 0.25-2) are investigated. The results reveal that the heat transport of base liquid is greatly influenced by these parameters. However, a fixed flow pattern persists in spite of variations in parameters. The heat transfer enhancement due to nanoparticles is assessed. Analysis shows an escalating rise in pumping power as Re increases above 100 and Da decreases below 10(-5). (C) 2017 Elsevier B.V. All rights reserved.