Difusão de massa em corpos cilíndricos: modelagem e desenvolvimento de software com aplicação à secagem de bananas.

Abstract

In several physical situations of interest, the diffusion theory is used to describe the transport of mass and/or heat in a medium. Among such situations, it is used to describe processes of heating and cooling of bodies, and also the absorption and desorption of fluids in porous solids. This work aims to study the transient diffusion in solids with cylindrical shape and, for such, analytical and numerical solutions of the diffusion equation for this geometry are presented, for the boundary conditions of the first and third kind. Regarding the numerical solution, the one-dimensional diffusion equation was discretized using the finite volume method, with a fully implicit formulation. As part of the study, a software on the Windows platform, using the programming language FORTRAN, including the User Interface was developed. It can be used both to simulate diffusive processes and to determine thermo-physical parameters, via optimization techniques. The developed computer package, mcluding programs involving optimizers, analytical and numerical solutions, was applied to study the thin-layer drying of bananas, using experimental data available in literature.