Permeability of porous ceramics considering the Klinkenberg and inertial effects

The literature reports that permeability constants differ in experiments co nducted with gases or liquids. This behavior, known as the Klinkenberg effe ct, has been explained based on the gas-slippage theory. We show here that inertial effects not considered by Darcy's law are the cause of variations in the gas permeability constant, k(gas) with the mean pressure, P-m. The d ependence of k(gas) and P-m on fluid flow is fully explained by the propose d model, based on Forchheimer's equation. The use of the gas-slippage theor y is unnecessary to explain variations in k(gas) obtained by Darcy's law.