Numerical and experimental characterization of internal heat and mass transfer during convective drying of papaya (Carica papaya L.)in a drying air stream

Abstract

This work consisted of simulating convective heat and mass transfers during the drying of papaya in a parallel air stream. The aim of this work was to simultaneously couple the two-dimensional heat and mass transfer equations in the product in order to predict the drying kinetics of the papaya. These papaya slices were arranged on a rack with a length (L) of 30 cm and thickness (E) of 5 mm. The Luikov equations thus established for this model were discretized using the implicit finite difference method and then solved simultaneously using the Matlab 2014 tool. Simulations of papaya drying were performed under the influence of drying air temperature (40, 50, and 60 °C), drying air velocity (0.5, 1 and 1.76 m/s), relative air humidity (20, 40, and 60%), and product thickness (4, 5, and 6 mm). The numerical simulation results allowed the prediction of the temperature and humidity distributions inside the product during the drying process. The predicted data from this model were compared to the experimental data. The results showed agreement between the predicted and experimental data with average relative errors of 5.21% and 4.35% for moisture ratio and product temperature, respectively.