Mathematical modeling of microwave assisted air drying of cylindrical carrot samples

Drying behavior of cylindrical samples of carrot was investigated in a microwave assisted air drying. A pilot -scale microwave assisted air dryer was set up for this purpose. Based on the simultaneous heat and mass transfer, a mathematical model was proposed for predicting the temperature and moisture distribution in the drying sample. Considering the carrot radiuses and the penetration depth of the electromagnetic waves, a uniform electric field strength distribution within the drying material was assumed in the proposed model. The heat loss due to surface evaporative cooling was also considered at the external boundaries. A numerical solution was developed for the proposed model using an implicit finite difference method. The model was validated by comparing the predicted data with the experimental data, obtained from different cylindrical carrot samples during drying. The effects of microwave power density and also drying air temperature on the moisture and temperature profiles were investigated.