Transporte de calor e massa em sólidos esferoidais oblatos via termodinâmica dos processos irreversíveis – Estudo de caso: secagem de lentilha.

Abstract

This work aims to study the drying of solids with oblate spheroidal geometry based on the thermodynamics of irreversible processes. Was proposed a mathematical model that describes the simultaneous heat and mass transfer (liquid and vapor) during the drying of capillary-porous bodies with complex geometry, considering the variable transport coefficients and equilibrium or convective boundary conditions at the surface solid. All differential governing equations were written in oblate spheroidal coordinate system and numerically solved through the finite volume numerical method. The proposed model was applied to predict the drying of lentil grain in different experimental conditions. Results of the moisture content, temperature, liquid, vapor and heat fluxes during the drying process were obtained, analyzed and compared with experimental data, obtaining good concordance. It was verified that zone closed to focal point of the lentil grain dry and heat faster, in consequence, these areas are more susceptible to the appearance of cracks and fissures which may compromise the quality of the product. In all experimental conditions the vapor flux is predominant in the drying process as compared to liquid flux.