Diffusion in heterogeneous media: lattices of parallelepipeds in a continuous phase
Richard Maling Barrer, John H. Petropoulos · British Journal of Applied Physics · 1961
A treatment has been given of the permeability of a heterogeneous medium consisting of a regular lattice of rectangular parallelepipeds in a continuum. Effects on the permeability due to surface resistances on the upstream and downstream faces of the parallelepipeds have been considered, and also aspects of the role of particle shape and orientation. The treatment provides an approach to the permeability of and fractionation by foam plastic membranes. When the disperse phase has molecular sieve properties, high continuous fractionation factors for appropriate composite membranes and mixtures of diffusants are found to be possible. The treatment is also valid for the thermal or electrical conductivity, permittivity, or magnetic permeability of such a lattice.