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Influence of Velocity Gradient on Optimisation of the Aggregation Process and Properties of Formed Aggregates Cover

Influence of Velocity Gradient on Optimisation of the Aggregation Process and Properties of Formed Aggregates

By: Pavel Polášek  
Open Access
|Sep 2011

Abstract

The follow up research into the IHDS process was carried out with a Couette device. The outcome of this study provides a comprehensive understanding of the effect that both the agitation intensity and the agitation time have on the kinetics and the mechanism of the aggregation process. The results obtained confirm the very favourable influence of high agitation intensity for the formation of more compact and dense aggregates than those formed by the accustomed flocculation conditions with low agitation intensity. This research also proved that the agitation intensity and time are the inherent means profoundly influencing the properties of the resultant aggregates such as their size, shape, density and homogeneity. Further, it was confirmed that the aggregation process passes through a minimum. Furthermore, it was verified that the aggregation process takes place in four consecutive phases, namely a) the phase of formation, b) the phase of compaction, c) the phase of a steady (equilibrium) state and d) most probably the phase of inner restructuring. The pattern of the aggregates development in these phases remains the same irrespective of the magnitude of the velocity gradient applied but the time at which these phases are completed is velocity gradient dependent. Last but not least this study proved that the dimensionless product Ca = G T = const. has no general validity.

DOI: https://doi.org/10.2478/v10098-011-0016-6 | Journal eISSN: 1338-4333 | Journal ISSN: 0042-790X
Language: English
Page range: 196 - 205
Published on: Sep 21, 2011
In partnership with: Paradigm Publishing Services
Publication frequency: 4 issues per year

© 2011 Pavel Polášek, published by Slovak Academy of Sciences, Institute of Hydrology
This work is licensed under the Creative Commons License.

Volume 59 (2011): Issue 3 (September 2011)