Numerical investigation of the respective roles of cohesive and hydrodynamic forces in aggregate restructuring under shear flow

Saxena, Akash; Kroll-Rabotin, Jean-Sébastien; Sanders, R. Sean

doi:10.1016/j.jcis.2021.08.208

Cited by 4 publications

(29 citation statements)

References 53 publications

(91 reference statements)

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“…Furthermore, the scaled values of the forces can be chosen to favor restructuring or breakage. Particularly, tangential forces are varied as they are known to make aggregates brittle resulting in less restructuring and therefore a higher probability of breakage. Aggregate evolution studies performed at a very low Reynolds number have shown that high tangential forces induce less restructuring , but more breakage .…”

Section: Results and Discussionmentioning

confidence: 99%

“…It is worth noting that R g , in the context of aggregates, is the ratio of the second moment of mass around the center of the aggregate to the total mass. When N is constant among two aggregates, a comparison of their dimensionless radius of gyration R g * also compares their densities; thus, R g * can be used to quantify both size and density . In this study, each aggregate has an initial fractal dimension D f = 2.3 and consists of 70 rigid primary spherical particles.…”

Section: Methodsmentioning

confidence: 99%

“…In other words, the results obtained from aggregate studies with a particular short-ranged particle–particle interaction model will be applicable to aggregates with other types of short-range interactions. Hence, only the maximum tangential and normal forces are considered in the characterization of internal interactions. , More details on the modeling and implementation of these forces are given in previous works. , …”

Section: Methodsmentioning

confidence: 99%

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Role of Flow Inertia in Aggregate Restructuring and Breakage at Finite Reynolds Numbers

2023

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Forces acting on aggregates depend on their properties, such as size and structure. Breakage rate, stable size, and structure of fractal aggregates in multiphase flows are strongly related to the imposed hydrodynamic forces. While these forces are prevalently viscous for finite Reynolds number conditions, flow inertia cannot be ignored, thereby requiring one to fully resolve the Navier−Stokes equations. To highlight the effect of flow inertia on aggregate evolution, numerical investigation of aggregate evolution in simple shear flow at the finite Reynolds number is conducted. The evolution of aggregates exposed to shear flow is tracked over time. Particle coupling with the flow is resolved with an immersed boundary method, and flow dynamics are solved using a lattice Boltzmann method. Particle dynamics are tracked by a discrete element method, accounting for interactions between primary particles composing the aggregates. Over the range of aggregate-scale Reynolds numbers tested, the breakage rate appears to be governed by the combined effect of momentum diffusion and the ratio of particle interaction forces to the hydrodynamic forces. For higher shear stresses, even when no stable size exists, breakage is not instantaneous because of momentum diffusion kinetics. Simulations with particle interaction forces scaled with the viscous drag, to isolate the effect of finite Reynolds hydrodynamics on aggregate evolution, show that flow inertia at such moderate aggregate Reynolds numbers has no impact on the morphology of nonbreaking aggregates but significantly favors breakage probability. This is a first-of-its-kind study that establishes the role of flow inertia in aggregate evolution. The findings present a novel perspective into breakage kinetics for systems in low but finite Reynolds number conditions.

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Section: Results and Discussionmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

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Role of Flow Inertia in Aggregate Restructuring and Breakage at Finite Reynolds Numbers

2023

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“…However, most of these models are not able to take into account the peculiar disordered structure of agglomerates, that often presents weak points and local heterogeneities, which may play an important role in the breakup mechanism (Horwatt et al, 1992). This suggested the use of discrete element methods (DEM), which are able to take into full account the structure of the agglomerates, including the role that each primary particle plays in the transmission of stresses (Blais et al, 2019;Frungieri & Vanni, 2017Saxena et al, 2022).…”

Section: Introductionmentioning

confidence: 99%

CFD-DEM characterization and population balance modelling of a dispersive mixing process

Frungieri

Boccardo

Buffo

et al. 2022

Chemical Engineering Science

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“…DEM simulations allow one to track the motion of each single particle composing the carrier aggregate, taking into account both the adhesive interaction between the primary particles and the interaction with the surrounding fluid. [19][20][21] Different degrees of complexity can be introduced in DEM simulations when modelling the fluid dynamics interactions between the suspending fluid and the solid particles. In the so-called free-draining approximation, each particle is assumed to experience the Stokes drag force, as if no other particle were in the flow.…”

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confidence: 99%

Response of shear‐activated nanotherapeutic particles in a clot‐obstructed blood vessel by CFD‐DEM simulations

et al. 2022

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In recent years, targeted drug delivery systems have been regarded as a promising solution to enhance the efficiency of treatments against clots in blood vessels. In this context, shear‐activated nanotherapeutics (SANTs) have been recently proposed. These are micrometric clusters of polymeric nanoparticles coated with a clot lysing agent. These drug carriers are stable under normal blood flow conditions, but they can be designed to undergo breakup right on the clot in response to the local increase in the hydrodynamic stress caused by the lumen restriction, effectively concentrating the active agent at the point of need. The aim of this work is to investigate the mechanical response of three potential drug carrier morphologies to the pathological flow field stress, typically encountered in obstructed blood vessels. Computational fluid dynamics simulations have been used to compare the viscous stress in arterial obstructions with the one in a microfluidic device, suitable for in vitro experimental tests. Discrete element method simulations built upon Stokesian dynamics were conducted to estimate the tensile stress distribution acting inside isostatic, random close packing, and hollow drug carriers. The results herein presented constitute a platform for a future experimental campaign and aim at establishing SANTs as a robust and broadly applicable targeting strategy.

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Numerical investigation of the respective roles of cohesive and hydrodynamic forces in aggregate restructuring under shear flow

Cited by 4 publications

References 53 publications

Role of Flow Inertia in Aggregate Restructuring and Breakage at Finite Reynolds Numbers

Role of Flow Inertia in Aggregate Restructuring and Breakage at Finite Reynolds Numbers

CFD-DEM characterization and population balance modelling of a dispersive mixing process

Response of shear‐activated nanotherapeutic particles in a clot‐obstructed blood vessel by CFD‐DEM simulations

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