Geometric models for incorporating solid accumulation at the nodes of open-cell foams

In open-cell foams solid lumps are often present at the intersection of struts, known as the nodes. In this study models available in the literature that represent foams with solid accumulation at the nodes are investigated and used to obtain predictive equations for the permeability (for both the Darcy and Forchheimer flow regimes) and specific surface area for given porosity and average pore diameter values. The majority of the predictive equations proposed for the specific surface area based on these models are novel contributions. Furthermore, a method is proposed for incorporating solid lumps at the nodes into the existing foam (or three-strut) rectangular Representative Unit Cell (RUC) model. The models obtained from the literature along with the node adjusted RUC model are compared to one another and to relevant experimental data from the literature for foams that have accumulation of solid matter present at the nodes. The node adjusted RUC model provides physically meaningful and satisfactory changes to the specific surface area and permeability predictions of the existing foam RUC model.