Intermittent Diffusion In The Modified Stefan Cell
A modification of the Stefan cell apparatus for the measurements of gaseous diffusion coefficients based on a
continuous weighting of the amount of the evaporated solvent throughout an assembly of a capillary tubes has been
developed and tested. The main result of the upgraded setup is the substantial shortening of the time interval required for
obtaining reliable data needed for diffusion coefficient calculation. Details and particulars of the diffusion process in the
setup are presented and discussed. Hereafter the modified Stefan cell has been used for experimental study of unsteady
diffusion in case of evaporation of acetone. The relevant numerical model of the specified transient process has been
implemented and used for the explanation of the experimental results.
Keywords— Stefan Cell, Solvent Evaporation, Unsteady Diffusion, COMSOL Multiphysics, Numerical Modelling.