Flow of gases in porous media

It is shown that of the three possible types of flow, i e. laminar, turbulent, and molecular, the flow of gases through a gas chromatography column is laminar. This does not rule out the existence of eddies, but the positions of the latter are fixed with respect to the porous medium, in contrast to the conditions which prevail in turbulent flow. This is followed by an account of the theory of flow of an ideal gas through an empty tube (Poiseuille's law) and through a tube filled with a porous medium (Darcy's law); of the theories intended for the calculation of the permeability of unconsolidated porous media, such as those used in gas chromatography; of the deviations from Darcy's law observed at high flow rates; and finally the theory of the viscosity of gases. The methods of calculating the principal quantities used in this field are described, and tables of viscosity and permeability values are given. The application of current theories of flow rate to problems arising from temperature and flow rate programming is discussed.