Pore-scale computational analyses of non-Darcy flow through highly porous structures with various degrees of geometrical complexity

This study relies on pore-scale direct computations of velocity fields within highly porous open-cell metal foams (OCF) characterized by differing geometrical attributes. The Navier-Stokes equations are solved across a suite of synthetically generated pore structures to assess relationships between attributes/patterns of the pore-scale flow field and OCF pore-structure. This study explores the effect of porosity and number of pores per inch (PPI) of the foam structures on the onset of non-Darcy flow, and values of Forchheimer coefficient and permeability of the system. The results show that the complexity of the pore flow patterns causes the onset of non-Darcy flow to occur at low values of Reynolds number (Re-k). The analyses encompass a wide range of values of Re-k corresponding to Darcy and non-Darcy flow regimes. The results suggest that permeability increases up to 30% by increasing porosity from 0.85 to 0.95, the corresponding onset of a non-Darcy flow regime taking place for Re-k = 1.77 and 1.44, respectively. Otherwise, a significant decrease of permeability is documented upon increasing the PPI value from 10 to 40, the corresponding onset of a non-Darcy flow regime taking place for Re-k = 1.77 and 0.28, respectively.