Applying XDEM to Analyze the Heat-up Process of Woody Biomass on a Backward Acting Grate

The objective of this study is analysis of heat-up process of wet woody particles on a backward acting grate including dynamics motion investigation by implementing XDEM （extended discrete element method） as a novel approach. In this method, the particles are resolved as the discrete phase （individual elements） coupled via heat, mass and momentum transfer to the continuous gas phase. The temperature of particulates along the backward acting grate is investigated by evaluating effects of operating parameters such as bar amplitude and period. Furthermore, the bar motion has effects largely on the heat-up process of the packed bed on the backward acting grate which is considered here as well. In other words, motion of particles caused by bar motion influences the heat transfer of particles and totally the packed bed. In fact, the particles＇ heat-up is performed by a radiative heat flux facing the packed bed surface so that heat transfer of particles as radiation and conduction with surrounding particles is taken into account in addition to convection heat transfer between particles and surrounding gas phase.

Experimental and numerical investigation of iron ore pellet firing using coupled CFD-DEM method

Iron ore pellets are the main feedstock in ironmaking processes. While extensive research has addressed numerical modeling of the iron ore pellet induration process, little effort has been made to describe the intricate thermochemical processes occurring within the reactor starting from the pellet and particularly at the intra-particle scale. In this regard, discrete-continuous methods like CFD-DEM can generate more realistic, irregular particle assemblies, which leads to significantly more accurate predictions of voidage variation, wall effects, temperature distribution, and associated mass transfer phenomena. This study presents a numerical model based on computational fluid dynamics (CFD) coupled with the discrete element method (DEM) to simulate the thermal induration process of iron ore pellets. The presented model solving heat, mass, and momentum conservation equations for both continuous and discrete phases, provides detailed information on the thermochemical aspects of the process. Pilot-scale induration experiment was conducted to validate model predictions in terms of thermal history and final conversion fraction. It was found that inlet charge specifications, such as particle and pellet size, significantly impact the productivity of pelletizing plants, highlighting the potential of the presented model to optimize the process and improve plant productivity.

XDEM multi-physics and multi-scale simulation technology: Review of DEM-CFD coupling, methodology and engineering applications

The extended discrete element method (XDEM) multi-physics and multi-scale simulation platform is being developed at the Institute of Computational Engineering, the University of Luxembourg. The platform is an advanced multi-physics simulation technology that combines flexibility and versatility to establish the next generation of multi-physics and multi-scale simulation tools. For this purpose, the simulation framework relies on coupling various predictive tools based on an Eulerian and Lagrangian approach. The Euleria n approach represents the wide field of con tinuum models;the Lagra ngian approach is perfect for characterising discrete phases. Continuum models thus include classical simulation tools, such as computational fluid dynamics simulation and finite element analysis, while an extended configuration of the classical discrete element method addresses the discrete (e.g., particulate) phase. Apart from predicting the trajectories of in dividual particles, XDEM-suite extends the application of the XDEM to estimating the thermodynamic state of each particle using advanced and optimised algorithms. The thermodynamic state may include temperature and species distributions due to chemical reaction and external heat sources. Hence, coupling these extended features with either computational fluid dynamics simulation or finite element analysis opens a wide range of applications as diverse as pharmaceuticals, agriculture, food processing, mining, construction and agricultural machinery, metals manufacturing, energy production and systems biology.