Possibilities and Limits of Computational Fluid Dynamics–Discrete Element Method Simulations in Process Engineering: A Review of Recent Advancements and Future Trends

Kieckhefen, Paul; Pietsch, Swantje; Dosta, Maksym; Heinrich, Stefan

doi:10.1146/annurev-chembioeng-110519-075414

Cited by 81 publications

(31 citation statements)

References 141 publications

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“…Future studies will be concerned with the application of different granulator geometries, like spouted beds that are used for coating (Pietsch et al, 2018), and scale-up to pilot-scale granulators with different mixing times (Diez et al, 2019), as well as utilization of the CFD-DEM method (Kieckhefen et al, 2020) to correlate mixing times and particle-scale drying conditions with the resulting surface structures.…”

Section: Discussionmentioning

confidence: 99%

Correlating Granule Surface Structure Morphology and Process Conditions in Fluidized Bed Layering Spray Granulation

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Kieckhefen

Pietsch

et al. 2022

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A workflow for developing a multidimensional, linear correlation between the process conditions during fluidized bed spray granulation and the surface morphology of the resulting granules is presented. Spray coating experiments with Cellets ® 500 particles and sodium benzoate solution were performed in a lab-scale fluidized bed varying liquid spray rate, fluidization air flow rate, fluidization air temperature, spray air temperature and spray atomization pressure. To characterize the surface structure, the surface roughness of the coated particles was quantified using confocal laser-scanning microscopy. The roughness was correlated to the process conditions, and the resulting correlation was rigorously analyzed for the importance and co-linearities of the individual process parameters using a principal component analysis. The surface roughness is strongly dependent on the spray rate of the coating solution, the fluidization air temperature and the atomization pressure at the nozzle. In general, wet process conditions and large droplets with a low initial velocity favor the formation of particles with a rough surface structure, while dry conditions and fine droplets with a high velocity result in granules with a smooth and compact coating layer.

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Section: Discussionmentioning

confidence: 99%

Correlating Granule Surface Structure Morphology and Process Conditions in Fluidized Bed Layering Spray Granulation

Orth

Kieckhefen

Pietsch

et al. 2022

KONA

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“…The motion of particles is described by Newton’s second law, and the acceleration is time-integrated to find the new velocities and positions. Initially, DEM was developed for the modeling of systems consisting of spherical particles [ 37 ], but nowadays, several extensions of DEM are used for non-spherical particles, the modeling of multiphase flows [ 38 ], or chemical reactions. The simulations presented in this contribution have been performed in the open-source DEM simulation framework MUSEN [ 39 ].…”

Section: Numerical Backgroundmentioning

confidence: 99%

Discrete Element Modeling and Electron Microscopy Investigation of Fatigue-Induced Microstructural Changes in Ultra-High-Performance Concrete

et al. 2021

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In view of the growing demand for sustainable and lightweight concrete structures, the use of ultra-high-performance concrete (UHPC) is becoming increasingly important. However, fatigue loads occur more frequently in nature than static loads. Despite the impressive mechanical properties of UHPC, a reduced tolerance for cyclic loading is known. For this reason, our paper deals with experimental and numerical investigations regarding the main causes for crack initiation on the meso, micro, and nanoscale. After mechanical fatigue tests, we use both scanning (SEM) and transmission electron microscopy (TEM) to characterize microstructural changes. A new rheological model was developed to apply those changes to the mesoscopic scale. The origins of fatigue damaging can be traced back to a transformation of nanoscale ettringite, resulting in a densification of the surrounding binder matrix. Additionally, a higher content of unhydrated cement clinker in the matrix benefits fatigue resistance. On the mesoscale, stress peaks around aggregate grains expand into the surrounding binder with increasing load cycles and lead to higher degradation.

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“…At the other extreme, i.e., the small-scale interaction between the fluid and individual particles, discrete-continuum (or Eulerian-Lagrangian) simulations based on the discrete element method appeared, thanks to the progress in the computational power, giving rise to the CFD-DEM (Computational Fluid Dynamics-Discrete Element Method) approach [6]. The recognition of the discrete nature of the granular medium proved to be a key ingredient and allowed important new features of fluidized systems to be captured, as discussed in several reviews (e.g., [7][8][9][10][11][12]).…”

Section: Introductionmentioning

confidence: 99%

Coarse-Grain DEM Modelling in Fluidized Bed Simulation: A Review

2021

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In the last decade, a few of the early attempts to bring CFD-DEM of fluidized beds beyond the limits of small, lab-scale units to larger scale systems have become popular. The simulation capabilities of the Discrete Element Method in multiphase flow and fluidized beds have largely benefitted by the improvements offered by coarse graining approaches. In fact, the number of real particles that can be simulated increases to the point that pilot-scale and some industrially relevant systems become approachable. Methodologically, coarse graining procedures have been introduced by various groups, resting on different physical backgrounds. The present review collects the most relevant contributions, critically proposing them within a unique, consistent framework for the derivations and nomenclature. Scaling for the contact forces, with the linear and Hertz-based approaches, for the hydrodynamic and cohesive forces is illustrated and discussed. The orders of magnitude computational savings are quantified as a function of the coarse graining degree. An overview of the recent applications in bubbling, spouted beds and circulating fluidized bed reactors is presented. Finally, new scaling, recent extensions and promising future directions are discussed in perspective. In addition to providing a compact compendium of the essential aspects, the review aims at stimulating further efforts in this promising field.

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Possibilities and Limits of Computational Fluid Dynamics–Discrete Element Method Simulations in Process Engineering: A Review of Recent Advancements and Future Trends

Cited by 81 publications

References 141 publications

Correlating Granule Surface Structure Morphology and Process Conditions in Fluidized Bed Layering Spray Granulation

Correlating Granule Surface Structure Morphology and Process Conditions in Fluidized Bed Layering Spray Granulation

Discrete Element Modeling and Electron Microscopy Investigation of Fatigue-Induced Microstructural Changes in Ultra-High-Performance Concrete

Coarse-Grain DEM Modelling in Fluidized Bed Simulation: A Review

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