A class of particulate problems suited to FDEM requiring accurate simulation of shape effects in packed granular structures

Abstract

In many granular material simulation applications, DEM capability is focused on the dynamic solid particulate flow properties and on systems in which millions of particles are involved. The time of relevance is many seconds or even minutes of real time. Simplifying assumptions are made to achieve run completion in practical timescales. There are certain applications, typically involving manufactured particles, where a representative pack is of the order of a thousand particles. More accurate capturing of the influence of complex shape is then often possible. Higher accuracies are necessary to model the topology of the void space, for example, for further CFD simulation and optimisation of fluid flow properties. Alternatively, the accuracy may be critical for structural performance and the force or stress transmission through the contact points is to be controlled to avoid material damage and poor function. This paper briefly summarises methods for simulation of shape effects on packing structures in the granular community and narrows the scope to problems where shape effects are of overriding concern. Two applications of mono-sized, mono-shaped packing problems are highlighted: catalyst support pellets in gas reforming and concrete armour units in breakwater structures. The clear advantages of FDEM for complex-shaped particle interactions in packed systems with relatively few particles are discussed. A class of particulate problems, 'FDEM-suited' problems, ones that are ideal to be solved by FDEM rather than by DEM, is proposed for science and engineering use.

Micromechanical description of the compaction of soft pentagon assemblies

“…On the other hand, introducing the correct particle shape deformations in numerical simulations with discrete element methods gives rise to various technical difficulties, mainly seen in the increase of the computational time. Regarding this, different discrete element strategies have been proposed, such as the bonded-particle method [32,33] and couplings between classical finite element or meshless methods [34][35][36][37][38][39]. The latter methods, although computationally expensive, have the advantage of closely representing the geometry of the particles.…”

Elements of the Manufacture and Properties of Technical Catalysts

“…The bed parameters, mentioned above, strongly influence single-phase and multiphase flow aspects, degree of pressure loss along the height of the bed, axial and radial dispersion qualities in common with interparticle and interparticle heat, and mass transfer properties. ,− For example, the pressure drop of a fluid passing through the packing is highly dependent on the size of the interparticle voids . Therefore, different researchers have studied the hydrodynamics, packing structure, and the filling of this type of the reactor modeling fixed-beds using Computational Fluid Dynamics (CFD) simulations based on the discrete element method (DEM) and Finite–Discrete Element Method (FDEM), ,− with subsequent flow, heat, and/or mass transfer simulation by known tools such as COMSOL Multiphysics, Ansys Fluent, STAR-CCM+,CFD-ACE+, or OpenFOAM, the latter being open source, allowing users the freedom to modify and extend its functionality. , If the reader wishes to dive deeper in this interesting topic, we recommend reading the interesting review by Hettel et al who discuss CFD analysis of catalytic reactors. In addition, the analysis made from such calculations that can be coupled to the multiscale modeling of the catalytic reactor .…”

Micromechanical description of the compaction of soft pentagon assemblies

“…On the other hand, introducing the correct particle shape deformations in numerical simulations with discrete element methods rises various technical difficulties, mainly seen in the increase of the computational time in the simulations. In this direction different discrete element strategies have been proposed, such as the Bonded-Particle Method [32,33] and couplings between classical finite element or mesh-less methods [34][35][36][37][38][39]. The latter methods, although computational expensive, have the advantage of closely represent the geometry of the particles.…”