A pore-scale model for predicting resistance of airflow through grain bulks

Abstract. A model is proposed to predict the resistance of airflow through the interconnected pores between grain kernels. The model is based on the tortuous airflow paths and a collection of a straight and three branching tubes along the airflow paths through grain bulks. The straight and three branching tubes are constructed from the Discrete Element Method (DEM) simulation of the grain bulks. The resistance to flow along a flow path is predicted as the total pressure drop of the straight tube and three branching tubes of each tetrahedron units. The predicted pressure drop is compared with the average pressure drop for airflow through grain beds in ASABE Standard and the pressure drop predicted by Ergun’s equation. The predicted total pressure drop for airflow through the widest airflow path is 17.9 Pa, which is close to the data from the ASABE Standard. It indicates that the pore-scale fluid flow model integrated with the DEM pore structure model is feasible to predict airflow resistance along the flow paths in grain bed.