A pore-scale network model is developed to model airflow through grain bulks. Grain kernels are modeled as spherical particles using the discrete element method (DEM). Based on the positions and diameters of grain kernels in the grain bulk, Delaunay tessellation is used to discretize the pore space into distinct tetrahedron elements representing individual pores. The overall pressure drop through the grain bed is obtained by solving a fundamental fluid mechanics equation for each tetrahedron unit atthe pore level. The resistance to flow along a flow path is predicted as the total pressure drop of all tetrahedron units along this path. The pressure drop of airflow through the grain bed predicted by the pore-scale network model is 1.32 Pa, which is greater than the pressure drop calculated by Ergun's equation (0.33 Pa), lower than the pressure drop recommended in the ASABE Standards (2 Pa) and the experimental results (2.24Pa).
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