A coarse grain model with parameter scaling of adhesion forces from liquid bridge forces and JKR theory in the discrete element method

Abstract

The discrete element method (DEM) is a reliable tool for analyzing powder processes. However, the DEM is problematic for fine particle simulations owing to its huge computational cost. Coarse grain models, where multiple original particles are replaced with one large particle, are a promising solution. In such a model, scaling laws for forces acting on a coarse-grained particle are used to make its behaviors match the behaviors of the original particles. While various scaling laws have been proposed, there is not enough insight into combining several scaling laws and the relationship between scaled parameters. This study newly proposes a coarse grain model with a systematic parameter scaling law for adhesion forces, especially liquid bridge forces. Simulation results are compared with experimental results. Good agreements are achieved for macroscopic particle behaviors such as cascading angles and lifted heights. The adequacy of the proposed coarse grain model is also verified. The behaviors of the coarse-grained particles well match the corresponding behaviors of the original particles. Consequently, this study demonstrates the superiority of the coarse grain model by comparing its results with those obtained without the model.