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 lo cal temperature-dependent effective diffusivity was considered. Temper ature calculation within the sample was performed using the macroscopi c 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 o n the model describing the heat and mass transfer. The effective diffu sivity was derived according to Arrhenius' law. For evaluation purpose s this model was applied to drying experiments in a range of air tempe ratures 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 t o explain more than 99.3% of the total variance.