Comparison of Mathematical Models to Simulate Aeration of Wheat Stored in Brazil

Equilibrium and non-equilibrium heat and mass balance models are compared to simulate aeration of stored wheat under tropical and subtropical climates using both linear and non-linear airflow distributions. The approach used was to compare deviations in predicted grain deterioration instead of deviations in grain moisture content and temperature. The results produced by the equilibrium and non-equilibrium models were significantly different ( P=0·05)when simulating aeration of wheat stored for 1 yr in Curitiba, Brazil because the deviations in grain deterioration were equal to or greater than the uncertainty in predicting deterioration (±30%) for most test conditions. The non-equilibrium model appears more appropriate than the equilibrium model for simulating aeration of stored wheat because it is based on experimental thin-layer drying and wetting equations and equilibrium moisture content equations for desorption and adsorption. In addition, the equilibrium model over-predicts wheat moisture content and temperature, causing an over-prediction of grain deterioration. It is concluded that a more accurate deterioration model is needed to increase the uncertainty in predicting wheat deterioration for simulated aeration of stored wheat.