Mathematical modelling of convective drying of feijoa (Acca sellowiana Berg) slices

Abstract

A two-dimensional mathematical model for coupled heat and mass transfer during convective drying of feijoa (Acca sellowiana Berg) slices was implemented. The thermophysical and transport properties were considered variable and the effective moisture diffusion coefficient was determined based on the Arrhenius-type temperature dependence. The convective heat and mass transfer coefficients were obtained from the minimization of the function in terms of the error of experimental and predicted data. The model was solved by means of the finite element method programmed in FreeFEM. This is a free software that has not been reported for fruit convective drying modelling, but this software can be used for drying modelling in fruits. The model was validated against experimental data for air velocities of 0.5 and 1 ms−1, temperatures of 50, 60, and 70 °C and slice thicknesses of 0.003 and 0.005 m through Lin's concordance correlation coefficient (ρc). Which has not been reported for validation in drying modelling though it is a reliable indicator of model agreement. Experimental data were well predicted with the model, with concordance correlation coefficients of 0.9653 and 0.9872 for moisture content and temperature, respectively. The model was found to be suitable to describe, with sufficient accuracy, the heat and mass transfer during drying, and hence, it is appropriate for engineering applications.