Effect of non-well-mixed compartment and bulk flow on diffusion through a pore

The assumptions of well-mixed and zero bulk flow in compartmental analysis are reexamined. Using Poiseuille flow inside and radial flow outside a pore, the mass-transfer equations are solved by perturbations on simple diffusion. Formulas are obtained for solute distribution, total mass transfer, and apparent permeability. The effects of non-well mixing and bulk flow are discussed.