Modelling of convective drying of potatoes polyhedrons

Abstract This work aimed to develop numerical models to predict the moisture content and deformation of potato slices during convective drying (40–80 °C, 0.5 m·s−1). Three-dimensional slices were considered in cylindrical, cubic, parallelepiped, and prism geometries. The first classic model coupled the linear constant drying rate period with the analytical solution of Fick’s law in spherical coordinates, evaluating the mass diffusion coefficients (4.2–15.5·10−10 m2·s−1), critical drying time (1640–5085 s), and critical moisture content (1.8–2.4 kg·kg−1). The Finite Element Method (FEM) was a more robust model, that combined momentum and mass transfer to three-dimensional solid deformation of polyhedrons by ALE method, evaluating the mass diffusivity (1.4–6.5·10−10 m2·s−1). The FEM model could predict the shrinkage due to water molar flux removal on moving solid boundaries and explain the pseudo-constant drying rate detected in experimental data. The developed models accurately described the drying of food materials with a high shrinkage ratio.