CFD-DEM simulations of particulate fouling in microchannels

Trofa, Marco; D’Avino, Gaetano; Sicignano, Luca; Tomaiuolo, Giovanna; Greco, Francesco; Maffettone, Pier Luca; Guido, Stefano

doi:10.1016/j.cej.2018.09.207

Cited by 38 publications

(23 citation statements)

References 49 publications

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“…The contact force and torque are calculated through the Hertz–Mindlin model [ 24 ]:

The tangential component of the contact force

is constrained by the well-known Coulomb law of friction

, in which

is the sliding friction coefficient. The other symbols are defined in Table 1 where

is the coefficient of restitution.…”

Section: Methodsmentioning

confidence: 99%

Nanoparticles Synthesis in Wet-Operating Stirred Media: Investigation on the Grinding Efficiency

2020

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The use of nanomaterials, thanks to their peculiar properties and versatility, is becoming central in an increasing number of scientific and engineering applications. At the same time, the growing concern towards environmental issues drives the seeking of alternative strategies for a safer and more sustainable production of nanoparticles. Here we focus on a low-energy, magnetically-driven wet milling technique for the synthesis of metal nanoparticles starting from a bulky solid. The proposed approach is simple, economical, sustainable, and provides numerous advantages, including the minimization of the nanoparticles air dispersion and a greater control over the final product. This process is investigated by experiments and discrete element method simulations to reproduce the movement of the grinding beads and study the collision dynamics. The effect of several parameters is analyzed, including the stirring bar velocity, its inclination, and the grinding bead size, to quantify the actual frequency, energy, and angle of collisions. Experiments reveal a non-monotonous effect of the stirring velocity on the abrasion efficiency, whereas numerical simulations highlight the prevalent tangential nature of collisions, which is only weakly affected by the stirring velocity. On the other hand, the stirring velocity affects the collision frequency and relative kinetic energy, suggesting the existence of an optimal parameters combination. Although a small variation of the stirring bar length does not significantly affect the collision dynamics, the use of grinding beads of different dimensions offers several tuning opportunities.

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“…The contact force and torque are calculated through the Hertz–Mindlin model [ 24 ]:

The tangential component of the contact force

is constrained by the well-known Coulomb law of friction

, in which

is the sliding friction coefficient. The other symbols are defined in Table 1 where

is the coefficient of restitution.…”

Section: Methodsmentioning

confidence: 99%

Nanoparticles Synthesis in Wet-Operating Stirred Media: Investigation on the Grinding Efficiency

2020

Self Cite

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“…In contrast, in our experiments, where the adhesion of a particle either with the wall or with other particles is rather weak and where the shear rate is greater than in this numerical study, only one particle at a time can be detached from the growing aggregate, and such event remains rare (Figures 7 and 8). This suggests that the choice of the adhesion condition between particles in numerical simulations has a dramatic impact on the aggregate growth, as was actually pointed out by Trofa et al [36]. In the future extensive numerical studies of a single pore clogging by colloidal particles should be performed by varying systematically the parameters of colloidal interaction potentials (particle-particle and the particle-wall) to better elucidate this influence.…”

Section: Discussionmentioning

confidence: 77%

“…Recently, advanced simulations have tackled the issue of clogging at the pore scale [31,[34][35][36]. Even though they take a great care of the hydrodynamics of particle capture as well as the DLVO forces, they do not feature deposition patterns similar to those observed in this work.…”

Section: Discussionmentioning

confidence: 83%

“…al. [36] need to "clue" particles on the pore surface, making sure that there is a uniform spatial distribution of the particles all along the pore surface, before running their pore clogging simulations. Very recently, Lohaus et al [34] used a coupled CFD-DEM with a more accurate description of the DLVO forces but they neglected the particle capture on top and bottom walls, focusing only on the laterals walls.…”

Section: Discussionmentioning

confidence: 99%

“…al. [36] included the coupling between the aggregate growth from a pore wall and the fluid around it, which is able to break some parts of the growing aggregate. They observed that large fragments of the aggregates, which involve tens of particles, can be detached by the flow.…”

Section: Discussionmentioning

confidence: 99%

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Dynamics of pore fouling by colloidal particles at the particle level

Dersoir

Schofield

Vincent

et al. 2019

Journal of Membrane Science

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Particle filtration occurs whenever particles flow through porous media such as membrane. Progressive capture or deposition of particles inside porous structure often leads to complete, and generally unwanted, fouling of the pores. Previously there has been no experimental work that has determined the particle dynamics of such a process at the pore level, since imaging the particles individually within the pores remains a challenge. Here, we overcome this issue by flowing fluorescently dyed particles through a model membrane, a microfluidic filter, imaged by a confocal microscope. This setup allows us to determine the temporal evolution of pore fouling at the particle level, from the first captured particle up to complete blocking of the pore. We show that from the very beginning of pore fouling the immobile particles inside the pore significantly participate in the capture of other flowing particles. For the first time it is determined how particles deposit inside the pore and form aggregates that eventually merge and block the pore.

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