Characterization of flow through packed bed of spheres with large particle diameters (0 similar to m) is important in industrial applications, such as mining, geothermal, oil and gas, and construction industries. In this study, a three-dimensional pore-scale mathematical model of packed bed of spheres with large particle diameters considering uniform and non-uniform particle size distributions is developed and validated against experimental data. It was found that the available correlations fail to predict flow behavior in packed bed with larger particle sizes. Hence, Ergun and Forchheimer theories along with pore-scale mathematical model are utilized to simulate and develop permeability (Carman-Kozeny) and inertial resistance (Forchheimer) correlations which are valid for flow through packed bed of spheres with large particle sizes, i.e. sphere diameter from 0.04 to 1.2 m and porosity between 0.2 and 0.7. The developed correlation can be used in either analytical or volume-averaged computational models which is useful for industrial/practical. Crown Copyright (C) 2019 Published by Elsevier B.V. All rights reserved.