A thermodynamic simulation model for storage of corn

Abstract

A mathematical simulation model based on the theories of transport phenomena and thermodynamics was developed to predict the storage behavior in a bed of corn. Coupled heat and mass transfer equations for a porous-capillary hygroscopic body were utilized in this study. The boundary conditions of heat and moisture were determined using the law of conservation, the law of heat and mass diffusion, and the law of convective heat and mass transfer. The system was solved using the implicit finite difference method with matrix inversion for an axisymmetric body with 36 annular elements. The bulk moisture diffusivities were determined using five mixing models(parallel, series, equivalent-resistor, modified Maxwell, and geometric mean). Five phase conversion factors(0.0, 0.25, 0.50, 0.75, and 1.0) were utilized to evaluate the five mixing models.

Three laboratory storage bins, and eight grain sample columns were designed and constructed. Three experiments were conducted to enable the determinations of temperature and moisture content within the interior of the storage bin. The simulation model was verified by comparing the predicted results with the experimental values. Results indicate that the geometric mean model with a phase conversion factor of zero was the best selection. A postulated path for internal moisture flow was suggested.