http://lattes.cnpq.br/4842950905522120; LIMA, Hallyson Gustavo Guedes de Morais.
Resumo:
The production of foodstuffs has increased with each passing year and unfortunately
so has the waste. In this way, the optimized studies of the processes are thus
increasingly for the conservation, the optimization and the optimization and the
processes more and more efficient. Seeking to improve the freeze-drying process of
fruits, this work presents a numerical and experimental study on the freeze-drying
process of tropical fruits. It was necessary to determine which coordinate system best
describes the geometry of tropical fruits, using the epheroid system of combinations. A
transient two-dimensional thermophysical model was developed in each of the
lyophilization phases to predict the heat transfer, considering the symmetry around the
center of the solid, constant properties and volume. The connection boundary solution
was calculated via the volume numerical method, considering a convection condition
on the solid surface. To validate the numerical methodology, freeze-drying experiments
were carried out with bananas of the Musa paradisiaca variety. The fruits were frozen
with freezing at temperatures of -51, -33, -28 and -27 °C, and drying in a freezing
chamber whose pressure in the freezing chamber was less than 1 mbar. Experimental
results of kinetics and fruits were shown and analyzed. It was found that the
temperature gain and loss curves of the fruits were influenced by the freeze-drying
phase. Theoretical results of fruit temperature were obtained from the experimental
results, allowing the determination of the convective heat download coefficients
compared. A good fit was observed between the predicted and experimental results