LAMMPS - a flexible simulation tool for particle-based materials modeling at the atomic, meso, and continuum scales

Discrete particle simulation of particulate systems: Theoretical developments

Discrete particle simulation of particulate systems: A review of major applications and findings

Gas-solid fluidized beds are widely applied in many chemical processes involving physical and/or chemical transformations, and for this reason they are the subject of intense research in chemical engineering science. Over the years, researchers have developed a large number of numerical models of gas-fluidized beds that describe gas-solid flow at different levels of detail. In this review, we discriminate these models on the basis of whether a Lagrangian or a Eulerian approach is used for the gas and/or particulate flow and subsequently classify them into five main categories, three of which we discuss in more detail. Specifically, these are resolved discrete particle models (also called direct numerical simulations), unresolved discrete particle models (also called discrete element models), and two-fluid models. For each of the levels of description, we give the general equations of motion and indicate how they can be solved numerically by finite-difference techniques, followed by some illustrative examples of a fluidized bed simulation. Finally, we address some of the challenges ahead in the multiscale modeling of gas-fluidized beds

Numerical Simulation of Dense Gas-Solid Fluidized Beds: A Multiscale Modeling Strategy

Distinct element modelling of non-spherical frictionless particle flow

Distinct element modelling of cubic particle packing and flow

This paper investigates the effect of particle angularity on general granular response concentrating on flow and stress-strain behaviour. A 2D polygon DEM model is developed to a 3D polyhedron model. The effect of particle shape on the response of polygons in simple shear and polyhedra under gravity flow is investigated using regular shapes with rounded vertices. The study concentrates on the angularity rather than aspect ratio by comparing circles, near squares and near equilateral triangles in 2D and spheres, tetrahedra and octahedra in 3D. In summary the more angular the particle the greater the resistance to the forcing load and the flowability is reduced. A mix of spheres and octahedra demonstrates an approximate linear combination of effects.

Particle shape effects in discrete element modelling of cohesive angular particles

Integration schemes and damping algorithms in distinct element models

Dyes have long been used in dyeing, paper and pulp, textiles, plastics, leather, paint, cosmetics and food industries. Nowadays, more than 100,000 commercial dyes are available with a total production of 700,000 tones manufactured all over the world annually. About 10-15% of dyes are being disposed off as a waste into the environment after dyeing process. This poses certain hazards and environmental problems. The objective of this study is to investigate the adsorption behavior of Methylene Blue (MB) from aqueous solution onto natural and acid activated Jordanian bentonite. Both bentonites are firstly characterized using XRD, FTIR and SEM techniques. Then batch adsorption experiments were conducted to investigate the effect of initial MB concentration, contact time, pH and temperature. It was found that the percentage of dye removal was improved from 75.8% for natural bentonite to reach 99.6% for acid treated bentonite. The rate of MB removal followed the pseudo second order model with a high correlation factor. The Langmuir and Freundlich adsorption models were applied to describe the equilibrium isotherms. The Langmuir isotherm model was found more representative. The results indicate that bentonite could be employed as a low cost adsorbent in wastewater treatment for the removal of colour and dyes.

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Feras Y. Fraige

Papers

Distinct element modelling of non-spherical frictionless particle flow

Distinct element modelling of cubic particle packing and flow

Particle shape effects in discrete element modelling of cohesive angular particles

Integration schemes and damping algorithms in distinct element models

Adsorption from aqueous solution onto natural and acid activated bentonite