Estudo da secagem convectiva de paralelepípedos de pera in natura e osmodesidratadas por meio de modelos difusivos tridimensionais com parâmetros variáveis

This research proposes mathematical models for the study of convective drying of fresh and osmodihydrated pears, as well as the estimation of process parameters using an optimizer coupled to numerical solutions of the three-dimensional diffusion equation in rectangular coordinates, with a third-type boundary condition. The models adopt variable mass effective diffusivity and product shrinkage inherent to convective drying. The numerical solutions were obtained using the finite volume method with a fully implicit formulation. The process parameters obtained were consistent with the literature, and the models showed good accuracy and several features that allowed the prediction and analysis of drying kinetics and rates as a function of time and average water content, in addition to the water content and diffusivity distributions in the pear samples. For all samples, a decreasing drying rate was observed in relation to the average water content. Furthermore, it was possible to analyze the kinetics of water content at specific points in the samples in relation to time, as well as the behavior of drying rates at these points as a function of time and water content. At the corners of the pear-shaped parallelepipeds, the drying rates showed similar behavior to the drying rate of the samples as a function of average water content. In the center of the samples, the drying rates showed intervals of increase and decrease in relation to time and water content.