Determination of the effective diffusion coefficient

Abstract

The equation for drying kinetics is obtained, base on the analytical solution of the differential equation with a boundary condition in the form of the flux. This equation was initially developed by G. Efremov. In this paper a modification of the Efremov drying equation will be presented. Shrinkage correction will be included in that equation for the first time. Two programs were designed to compute the effective diffusion coefficient. First program did not include shrinkage effect during drying into the computation algorithm while the second one has included it. Two models for predicting the drying behavior were obtained as the result of cited programs calculation. First model did not include shrinkage (model 1) and second one (model 2) has included it. The predicted values obtained from model 2 fit with experimental data. Results presented in this study showed that the values of effective diffusion coefficient determined by designed computer programs have similar values with values available in literature related to the same coefficient determined for different clays.