### Abstract

Language | English |
---|---|

Pages | 577-589 |

Number of pages | 13 |

Journal | Journal of Colloid and Interface Science |

Volume | 319 |

Issue number | 2 |

DOIs | |

Publication status | Published - 15 Mar 2008 |

### Fingerprint

### Keywords

- aggregation
- breakage
- turbulent conditions
- polystyrene particles
- shear rate effect
- solid volume fraction effect
- aggregation efficiency
- steady-state reversibility
- aggregate morphology
- light scattering
- image analysis
- aggregate cohesive force

### Cite this

*Journal of Colloid and Interface Science*,

*319*(2), 577-589. https://doi.org/10.1016/j.jcis.2007.12.005

}

*Journal of Colloid and Interface Science*, vol. 319, no. 2, pp. 577-589. https://doi.org/10.1016/j.jcis.2007.12.005

**Effect of shear rate on aggregate size and morphology investigated under turbulent conditions in stirred tank.** / Soos, Miroslav; Moussa, Amgad S.; Ehrl, Lyonel; Sefcik, Jan; Wu, Hua; Morbidelli, Massimo.

Research output: Contribution to journal › Article

TY - JOUR

T1 - Effect of shear rate on aggregate size and morphology investigated under turbulent conditions in stirred tank

AU - Soos, Miroslav

AU - Moussa, Amgad S.

AU - Ehrl, Lyonel

AU - Sefcik, Jan

AU - Wu, Hua

AU - Morbidelli, Massimo

PY - 2008/3/15

Y1 - 2008/3/15

N2 - Aggregation and breakage of aggregates produced from fully destabilized polystyrene latex particles in turbulent flow was studied experimentally in both batch and continuous stirred tank. Detailed investigation of the initial kinetics showed that the collision efficiency, alpha, depends on the shear rate G according to alpha proportional to G(-b), with a power law exponent, b, equal to 0.18. After steady state was reached the dynamic response of the system on a change in stirring speed and solid volume fraction was investigated. It was found that the steady-state values of two measured moments of the cluster mass distribution (CMD) are fully reversible upon a change in stirring speed. This indicates that although the moments of CMD at steady-state depend on the applied shear rate, the aggregate structure is independent of the shear rate in the given range of stirring speeds. This was proved by independent measurement of the fractal dimension, d(f), using image analysis which provided a df equal to 2.62 +/- 0.18 independent of applied stirring speed. The critical aggregate size, below which breakage is negligible, determined by dilution experiments was consequently used to evaluate the aggregate cohesive force holding the aggregate together, which was found to be independent of the aggregate size and equal to 6.2 +/- 1.0 nN.

AB - Aggregation and breakage of aggregates produced from fully destabilized polystyrene latex particles in turbulent flow was studied experimentally in both batch and continuous stirred tank. Detailed investigation of the initial kinetics showed that the collision efficiency, alpha, depends on the shear rate G according to alpha proportional to G(-b), with a power law exponent, b, equal to 0.18. After steady state was reached the dynamic response of the system on a change in stirring speed and solid volume fraction was investigated. It was found that the steady-state values of two measured moments of the cluster mass distribution (CMD) are fully reversible upon a change in stirring speed. This indicates that although the moments of CMD at steady-state depend on the applied shear rate, the aggregate structure is independent of the shear rate in the given range of stirring speeds. This was proved by independent measurement of the fractal dimension, d(f), using image analysis which provided a df equal to 2.62 +/- 0.18 independent of applied stirring speed. The critical aggregate size, below which breakage is negligible, determined by dilution experiments was consequently used to evaluate the aggregate cohesive force holding the aggregate together, which was found to be independent of the aggregate size and equal to 6.2 +/- 1.0 nN.

KW - aggregation

KW - breakage

KW - turbulent conditions

KW - polystyrene particles

KW - shear rate effect

KW - solid volume fraction effect

KW - aggregation efficiency

KW - steady-state reversibility

KW - aggregate morphology

KW - light scattering

KW - image analysis

KW - aggregate cohesive force

UR - http://www.elsevier.com/wps/find/journaldescription.cws_home/622861/description#description

U2 - 10.1016/j.jcis.2007.12.005

DO - 10.1016/j.jcis.2007.12.005

M3 - Article

VL - 319

SP - 577

EP - 589

JO - Journal of Colloid and Interface Science

T2 - Journal of Colloid and Interface Science

JF - Journal of Colloid and Interface Science

SN - 0021-9797

IS - 2

ER -