Airflow simulation and inlet pressure profile optimization of a grain storage bin aeration system

Abstract

The quality and conservation of grains depends directly on the storage system. Storage problems and inefficiency can lead to significant losses of the stored product, and high expenditure in energy and resources. To minimize these losses, an adequate and efficient aeration system is important, covering a uniform airflow throughout the grain mass domain. In order to have a good aeration system, a mathematical model and software were developed to simulate the distribution of 3D airflow in horizontal bulk storage bins during the aeration process under nonhomogeneous and anisotropic conditions. The criterion of evaluation of the specific airflow and the criterion of optimization of the aeration system were incorporated in the model. With the results, it was possible to perform the analysis of the air pressure, global and local specific airflow rate, and air velocity throughout the grain mass domain. Pressure data were obtained on a real storage system. The data obtained in the simulation were validated with observational, showing good agreement. Observational data of the pressure at different depths of the grain mass were obtained. An optimized aeration inlet air pressure profile was proposed, aiming at greater uniformity of the local specific flow distribution. The proposed theoretical air inlet profile allowed an 85.3% decrease in the airflow variation, but an 150% increase in maximum inlet air pressure at the centre of the storage bin was necessary. It could be used as a guideline for a new aeration system design.