Aggregation in mixing tanks - the role of inter-particle forces

Jee Wen Lim, J. J. Derksen* (Corresponding Author)

*Corresponding author for this work

Research output: Contribution to journalArticle

Abstract

We study aggregation of equally-sized spherical particles under mildly turbulent flow conditions (Reynolds numbers in the range 4000 to 8000) in a mixing tank through numerical simulation. The dynamics of the liquid flow is solved in terms of the volume-averaged Navier-Stokes equations by an extended lattice-Boltzmann method on a fixed uniform cubic grid. The particle dynamics is updated through applying Newton’s second law to each particle. The simulations include a two-parameter model for the attractive force between the particles that causes aggregation. The dynamics of solids and liquid are two-way coupled through a mapping procedure. An overall solids volume fraction of 10% has been
investigated. The level of aggregation of particles in the mixing tank mainly depends on the strength of the attractive force and on the impeller-based Reynolds number, not so much on the distance over which the aggregative force is active. A higher Reynolds number leads to less aggregation.
Original languageEnglish
JournalChemical Engineering Research & Design
Early online date16 Oct 2019
DOIs
Publication statusE-pub ahead of print - 16 Oct 2019

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Agglomeration
Reynolds number
Liquids
Navier Stokes equations
Turbulent flow
Volume fraction
Computer simulation

Keywords

  • Solids suspension
  • turbulent flow
  • lattice-Boltzmann method
  • aggregation
  • two-way coupling
  • EulerianLagrangian simulation

Cite this

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title = "Aggregation in mixing tanks - the role of inter-particle forces",
abstract = "We study aggregation of equally-sized spherical particles under mildly turbulent flow conditions (Reynolds numbers in the range 4000 to 8000) in a mixing tank through numerical simulation. The dynamics of the liquid flow is solved in terms of the volume-averaged Navier-Stokes equations by an extended lattice-Boltzmann method on a fixed uniform cubic grid. The particle dynamics is updated through applying Newton’s second law to each particle. The simulations include a two-parameter model for the attractive force between the particles that causes aggregation. The dynamics of solids and liquid are two-way coupled through a mapping procedure. An overall solids volume fraction of 10{\%} has beeninvestigated. The level of aggregation of particles in the mixing tank mainly depends on the strength of the attractive force and on the impeller-based Reynolds number, not so much on the distance over which the aggregative force is active. A higher Reynolds number leads to less aggregation.",
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AU - Lim, Jee Wen

AU - Derksen, J. J.

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N2 - We study aggregation of equally-sized spherical particles under mildly turbulent flow conditions (Reynolds numbers in the range 4000 to 8000) in a mixing tank through numerical simulation. The dynamics of the liquid flow is solved in terms of the volume-averaged Navier-Stokes equations by an extended lattice-Boltzmann method on a fixed uniform cubic grid. The particle dynamics is updated through applying Newton’s second law to each particle. The simulations include a two-parameter model for the attractive force between the particles that causes aggregation. The dynamics of solids and liquid are two-way coupled through a mapping procedure. An overall solids volume fraction of 10% has beeninvestigated. The level of aggregation of particles in the mixing tank mainly depends on the strength of the attractive force and on the impeller-based Reynolds number, not so much on the distance over which the aggregative force is active. A higher Reynolds number leads to less aggregation.

AB - We study aggregation of equally-sized spherical particles under mildly turbulent flow conditions (Reynolds numbers in the range 4000 to 8000) in a mixing tank through numerical simulation. The dynamics of the liquid flow is solved in terms of the volume-averaged Navier-Stokes equations by an extended lattice-Boltzmann method on a fixed uniform cubic grid. The particle dynamics is updated through applying Newton’s second law to each particle. The simulations include a two-parameter model for the attractive force between the particles that causes aggregation. The dynamics of solids and liquid are two-way coupled through a mapping procedure. An overall solids volume fraction of 10% has beeninvestigated. The level of aggregation of particles in the mixing tank mainly depends on the strength of the attractive force and on the impeller-based Reynolds number, not so much on the distance over which the aggregative force is active. A higher Reynolds number leads to less aggregation.

KW - Solids suspension

KW - turbulent flow

KW - lattice-Boltzmann method

KW - aggregation

KW - two-way coupling

KW - EulerianLagrangian simulation

U2 - 10.1016/j.cherd.2019.08.012

DO - 10.1016/j.cherd.2019.08.012

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JF - Chemical Engineering Research & Design

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