Influence of the Geometry on the Numerical Simulation of Isothermal Drying Kinetics of Bananas

The effect of the geometric representation of bananas on the numerical simulation of its isothermal drying kinetics is studied. To study that effect, it is supposed that the diffusion model describes satisfactorily the drying process with boundary condition of the first type and diffusivity varying as a function of the local moisture content. The geometries used to represent the banana are: infinite cylinder, finite cylinder and ellipsoid. In order to simulate the drying kinetics, the diffusion equation was solved through the finite volume method, with a fully implicit formulation, using cylindrical and generalized coordinates. In the analyses it was used experimental data available in the literature and the expressions for diffusivities were determined through optimization, using inverse method. The best model in the representation of the banana’s shape was the ellipsoid but the time demanded in its optimization was about 100 times greater than the time for the infinite cylinder.