Pore-scale direct numerical simulation of fluid dynamics, conduction and convection heat transfer in open-cell Voronoi porous foams

Abstract

The pore-scale analysis includes the pore network simulation and direct numerical simulation, which the latter is more accurate and provides more details about the problem. This study presents a pore-scale direct numerical simulation of flow and convection-conduction heat transfer in open-cell metal foams with a complex structure. First, using the Laguerre–Voronoi tessellations (LVT) algorithm, three foam samples with various porosities (76.6%, 84.4%, and 93.8%) and a constant pore density of 20 pores per inch (PPI) are generated. Next, the open-source library of OpenFOAM is employed to perform heat transfer and flow analysis in Darcy and non-Darcy regimes. Results were verified through comparison with available experimental and numerical data. The effects of foams' porosity, solid material, and Reynolds number on flow characteristics and heat transfer are investigated. Results are presented in terms of the permeability, Forchheimer coefficient, the volumetric and average heat transfer coefficient, and temperature and velocity distribution. By decreasing porosity, the flow complexity increases with subsequent increments in heat transfer and pressure drop. Also, the conductive heat transfer through the foam plays a vital role in the total heat transfer rate. These pore-scale outcomes could be used in macro-scale thermo-fluid models to perform more accurate simulations with less computational costs.