Mathematical and numerical modelling of coupled heat and moisture diffusions during infrared drying of a potato slice

This work presents a mathematical model and solves it numerically to investigate the diffusion of heat and moisture during drying of a potato slice in the presence of infrared rays. The energy and species (i.e., the moisture content) conservation equations are considered here to model the drying process. The energy equation of the model includes a suitable volumetric heat source to represent the infrared rays to heat the potato slice and evaporate the moisture. The distribution of temperature and moisture content within the potato slice is predicted numerically and validated with published experimental data. With a good agreement, the simulation is extended further for parametric studies. It is found that the evaporation rate increases initially with time, and then it remains almost constant. It increases with the square of the infrared temperature. The heat and moisture transfer coefficients are then predicted under different infrared temperatures. Finally, the correlations as a function of the infrared temperature and processing time are developed to describe the drying process. A correlation for the drying time of the potato slice under different infrared temperatures is also presented.