Three-Dimensional Modeling and Simulation of Heat and Mass Transfer Processes in Porous Media: An Application for Maize Stored in a Flat Bin

Abstract

If the relative humidity and temperature of the air inside a granular mass of stored grain exceeds a certain threshold value, microorganism activity is likely to increase. Lower relative humidity and temperature, when uniformly distributed inside the grain mass, prevent moisture migration and an increase in microorganism activity. To cool down or maintain the temperature of the grain mass below a threshold value, forced ventilation with an appropriate airflow can be used to remove excess moisture or heat generated by grain or microorganism respiration. The objective of this work was to solve the equations that describe the conservation of heat, mass, and momentum in order to predict heat and mass transfer processes in the environment inside a grain mass of maize, stored in a flat bin. Three-dimensional computational fluid dynamics was used to solve the equations. The analysis of heat and mass transfer was performed considering the geometry of a two-ton-capacity bin prototype using a hexahedral mesh for the finite volume analysis. The numerical grid was defined to discretize the physical flow domain of interest to calculate velocity, temperature, and moisture distribution in the bulk of stored grain. The predicted results were compared with experimental data, and the agreement between them was very good.

Keywords:

• CFD modeling
• Cooling process
• Finite volume
• Grain storage
• Heat and mass transfer

ACKNOWLEDGMENTS

We are grateful to the National Council of Technological and Scientific Development (CNPq – Brazil), the Foundation of Research Support of the Minas Gerais State (FAPEMIG – Brazil), and the Brazilian Federal Agency for Support and Evaluation of Graduate Education (CAPES – Brazil) for financial support of this project. We also thank the Federal University of Viçosa (UFV) for this great opportunity.