Development and Validation of a New Finite Element Stored Grain Ecosystem Model

An axisymmetric finite element model was developed that predicts the heat, mass, and momentum transfer that occurs in upright corrugated steel storage structures due to conduction, diffusion, and natural convection using realistic boundary conditions. Hourly weather data that included total solar radiation, wind speed, ambient temperature, and relative humidity were used to model the temperature and moisture content during ambient and chilled aeration and non-aerated storage. Periods of aeration were simulated assuming a uniform airflow rate through the grain mass. Heat and mass balances were used to calculate the temperature and absolute humidity in the headspace and plenum, based on solar radiation, wind, ambient conditions, air infiltration, convective heat and mass transfer from the grain surface, and permeable boundaries that allowed natural convection currents to cross grain surfaces. A heat balance was used to estimate the wall temperature. Sixteen pilot bins with a capacity of 11.7 t with temperature cables were available to validate the model. The model was validated using two years of measured corn temperatures and moisture contents during summer storage with non-aerated, ambient and chilled aeration. The average standard error between the experimental and predicted temperature was 2.4°C (1.1 to 5.7°C range) and the moisture content was 0.7 percentage points.