Maintaining the quality o f grains in storage over long periods of time is dependent on several factors, including the provision of a functional aeration system and an adequate management strategy. The growth and activities of insects in stored grains is a function of time, grain moisture content and grain temperature, but this can be controlled with effective aeration. To ensure effective aeration the conditions of the grains in storage must be monitored. Though several models exist for the prediction of grain moisture contents during aeration, most of these models assume airflow to be uniform during aeration. Thompson’s model which is commonly used for predicting grain moisture content assumes uniform airflow during aeration. Conversely, airflow is non-uniform in hopper bottom silos and partially perforated floors. Therefore the objective of this study is to modify Thompson’s model used for natural drying so it could be used to predict the moisture contents of grains during aeration when non-uniform flow of air is considered. A hopper bottom silo of 3m radius filled to a grain height of 1.8m was used for this study. Four tests, each test under different testing conditions and lasting 120 hours, were carried out to investigate the non-uniform movement of air. The investigations revealed that the modified model presented in this study is useful for predicting moisture content to within 0.5% of measured moisture content when non-uniform airflow is considered. The coefficient of determination (R2) between the measured and predicted values obtained for the moisture tests ranged from 0.97 to 0.98.
展开▼
