HEAT AND MASS-TRANSFER MODEL FOR POTATO DRYING

A model describing the mass and heat transfer during hot air drying of potato cubes was evaluated. A moving boundary problem as well as a local temperature-dependent effective diffusivity was considered. Temperature calculation within the sample was performed using the macroscopic heat transfer balance. The moving boundary problem was solved by an explicit finite difference method using experimental time and moisture data of an experiment carried out at 90 degrees C by identification on the model describing the heat and mass transfer. The effective diffusivity was derived according to Arrhenius' law. For evaluation purposes this model was applied to drying experiments in a range of air temperatures between 30 degrees C and 90 degrees C and cube sizes between 8 and 15 cm. The model permits a good process description allowing us to explain more than 99.3% of the total variance.