Mass diffusion in multilayer systems: an electrical analogue modelling approach

We develop a lumped parameter model to describe and predict the mass release of (absorption from) an arbitrary shaped body of any dimension in a large environment. Through the one-to-one analogy between diffusion-dominated mass transfer systems and electrical circuits we provide exact solutions in terms of averaged concentrations and mass released. An estimate of the release and characteristic time is also given. The proposed electrical analogue approach allows the definition of a time constant and lets an easy extension to a multi-layer and multi-phase cases. The simulation results are compared with those obtained from the solution of the corresponding analytical and numerical solutions, showing a good agreement.