Permeability of ceramic foams to compressible and incompressible flow

Ceramic foams constitute a new structural material characterized by a high porosity and high superficial area, formed by megapores interconnected by filaments. This results in a structure with low resistance to fluid flow, and to their use as filter. This work investigates the influence of several structural parameters, such as porosity, tortuosity, surface area and pore diameter, in predicting the permeability of ceramic foams. Foams with different pore densities were used as porous media. The permeability was measured utilizing air and water as flowing fluids, the former taken as an ideal gas and the latter as incompressible. No existing correlation was able to predict the permeability in the whole range studied. An Ergun-type correlation was fitted to the data, and represented very well the permeability of the media for all the foams, flowing fluids and operational range studied. Pore diameter was the structural parameter that best represented the media.