AN ANALYTICAL MODEL FOR MOISTURE DIFFUSION IN SOLID OBJECTS DURING DRYING

An analytical model is proposed to determine the moisture diffusivitie s in geometrical solid objects (namely, infinite slab, infinite cylind er, sphere) subjected to drying applications. The analysis for moistur e diffusion is carried out on the basis of two important criteria: 0.1 <Bi<100 and Bi>100. New correlations for the roots of the characterist ic equations corresponding these objects are developed. For a drying a pplication, Using the similarity between cooling and drying profiles, drying coefficient and lag factor are obtained. The model is then veri fied using available data from literature. Results show that the prese nted model can be used to determine the moisture diffusion coefficient s in such solid objects in a simple and accurate manner in a variety o f drying applications.