Modeling the effect of moisture on the flowability of a granular material

The flowability of granular materials is a crucial parameter to consider that impacts many engineering and industrial applications such as slope stability, powder handling and storage. The dependence of mechanical properties of granular materials on their water content is widely encountered but poorly understood. This paper presents a three-dimensional (3D) discrete element method model to simulate the microscale mechanisms of granular materials in terms of interactions between individual particles as well as interactions with surrounding fluid through liquid bridging. Formulation of the contact model is first introduced. Then the numerical model is validated by comparing the simulation results with experimental data reported in literature. Direct shear, repose angle and rotary drum tests are simulated with a synthetic material under various moisture contents. The effects of moisture on the shear strength and flowability are evaluated. The simulation results show that the numerical model presented in this paper is capable of reproducing the dependency of the shear strength on water content. Moreover, it also successfully captures the characteristics of particle flow under wet conditions.