MODELING OF MOISTURE-CONTENT OF GRAIN DURING STORAGE WITH AERATION

Two 6.6-m-diameter steel bins filled with 99.3 t of Hard Red Winter wheat were used for observing seasonal grain temperature and moisture content variations. Aeration in one bin was controlled manually with temperature limit settings. Aeration in the second bin was controlled by a programmable microprocessor using ambient air temperature and humidity and grain moisture content as the control parameters. A model was developed to predict grain moisture content and its distribution within the grain mass during storage. The model was based on a two-dimensional mass transfer equation with the associated boundary conditions and was solved using the finite difference method for cylindrical geometry. Local hourly weather data and airflow rates during aeration periods were used as model inputs. Predicted and measured grain moisture contents were in close agreement for a storage period of 15 months. The model and the parameter values determined provide moisture content and distribution predictions for stored wheat with and without aeration.