Técnicas analíticas e numéricas para a secagem de sólidos na forma de paralelepípedo: uma abordagem tridimensional.

Abstract

This work aims to propose techniques analytical and numerical to describe a transient diffusion process in a medium parallelepiped shaped, including finite and infinite labs. This study presents some solutions of the diffusion equation in media where the boundary condition of the third kind is appropriate. Analytical and numerical tools for the study of diffusion phenomena have been developed, involving the three geometries mentioned. In order to obtain a numerical solution, the three-dimensional diffusion equation was discretized by the finite volume method with a fully implicit formulation, using Cartesian coordinates. Software was developed on the Windows platform, using the Fortran programming language, including the graphical user interface. The software has generated consistent and coherent results in all tests performed; and it was validated for both: constant and variable thermo-physical parameters. We can conclude that the tools developed are appropriate for the study of diffusive problems in general. Such tools were applied in the description of data available in the literature on the drying of lumber of wood, and in original data on drying ceramic coating. The obtained results were discussed and analyzed. According to all obtained results, the proposed techniques are efficient to describe drying of solids parallelepiped shaped, using the liquid diffusion theory.