Experimental and Numerical Analysis of Permeability in Porous Media

Using scaffold microstructure for bone tissue graft has been widely considered. Among the several properties of a scaffold, permeability plays a prominent role in the transport of nutrients, oxygen, and minerals. It is a key parameter which comprises various geometrical features such as pore shape, pore size and interconnectivity, porosity, and specific surface area. The main aim of this research is to characterize the permeability of the scaffold microstructure in terms of different pore sizes and porosity. To this end, cylindrical geometries for pores were modeled and the permeability coefficient was calculated using velocity and pressure drop and employing Darcy’s law. The validation process of the numerical results was done by comparing with experimental data. In this regard, a simple experiment setup was presented based on the constant head method. Additionally, the scaffolds were built using Solid Freeform Fabrication (SFF) techniques. The results showed that increasing porosity leads to an increase in permeability. Moreover, the permeability increases as the pore size increases. Eventually, the reducing pore diameters have a significant effect on the flow and hence permeability (e.g., a 20% decrease in diameter yields a 76% decrease in permeability).