I. The Permeability of a Bed of Smooth Spherical Particles. II. Non-Steady Flow of Gas through a Porous Wall

Part I The resistance of a bed of smooth spherical particles to gas flow in both Darcy and quasi-turbulent regimes was investigated experimentally in order to check the accuracy of two conflicting resistance equations widely reported in the literature. Variations in specific surface and porosity of the bed independent of one another were realized by the use of spheres of different sizes systematically packed in different configurations. The experimental results are correlated on the basis of a general pressure drop equation defining two length parameters which are necessary for complete characterization of an arbitrary porous structure. These results are used to extend the range of validity of the more accurate of the two conflicting sphere bed resistance expressions. A general definition of the Reynold number of a fluid flowing through a porous structure of arbitrary complexity is suggested, and the special conditions which permit a sphere bed to be characterized by a single length parameter are discussed. Part II The results of a calculation of the time required for establishment of steady flow of gas through a porous wall following the sudden application of a pressure difference across the wall are presented in dimensionless form. The calculation was made by using an electrical analogy to satisfy the non-linear partial differential equation governing the pressure distribution in the wall.