Turbulent Aggregation of Alumina in Water andn-Heptane

✍ Scribed by Hubert Saint-Raymond; Frédéric Gruy; Michel Cournil

• Publisher: Elsevier Science
• Year: 1998
• Tongue: English
• Weight: 271 KB
• Volume: 202
• Category: Article
• ISSN: 0021-9797
• DOI: 10.1006/jcis.1998.5436

✦ Synopsis

THEORETICAL BACKGROUND Aggregation of alumina powder in water and n-heptane is followed by turbidimetry in situ. The experiments are carried out Turbulence under turbulent conditions. They are discussed in the framework

In this work, we adopt the classical description of turbuof a model which takes into account the hydrodynamic and physilence as presented in (1-4). At any instant and in any place cochemical aspects of aggregation. A good agreement between measured and predicted turbidity is found provided the aggregates of the turbulent flow, eddies are supposed to appear and to are considered as noncompact and liable to undergo fragmentatake part in the energy dissipation. Energy is supplied to tion. Recent models of aggregation and fragmentation of fractalthe flow by an external source, such as mechanical stirring. like clusters are successfully tested. The aggregate morphology Energy is transferred from the largest eddies to the smallest seems to depend on the nature of the liquid medium, however, eddies in which it is dissipated through viscous interactions.

not on the stirring rate. ᭧ 1998 Academic Press

The size of these smallest eddies is the Kolmogorov micro-Key Words: aggregation; fractal; turbulence; breakage; turbidimscale h; from dimensionless considerations h is expressed etry; light scattering. as a function of the kinematic viscosity n and the energy dissipation rate per unit mass e m in the form