Separation flow in matrices - redefinition of friction coefficients

Separation flow through matrices or membranes is generally characterized by three phenomenological coefficients. Of these the hydraulic permeability Lp and the reflection coefficient sigma are the most commonly discussed. Their theoretical interpretation is much aided by the use of friction coefficients flm defined to characterize the relative interaction in flow of the thermodynamic component l in its movement past m. It is shown that this definition can be further simplified and that as a result simplified expressions notable for Lp result.