- Title
- Influence of aggregate structure on suspension yield stress: a numerical study
- Creator
- Peng, Zhengbiao; Doroodchi, Elham; Evans, Geoffrey M.
- Relation
- CHEMECA 2011: Engineering a Better World. CHEMECA 2011: Engineering a Better World (Sydney 18-21 September, 2011)
- Relation
- http://www.conference.net.au/chemeca2011
- Publisher
- Engineers Australia
- Resource Type
- conference paper
- Date
- 2011
- Description
- This study theoretically examined the effect of aggregate structure on the suspension yield stress. The aggregation process of colloidal particles was simulated using the discrete element model (DEM) combined with the well-known DLVO theory. The predicted aggregate structural characteristics, namely the coordination number, and inter-particle forces were then used in a modified version of the Flatt and Brown mechanistic model [J. Am. Ceram. Soc. 89 (2006) 1244-1256] to calculate the corresponding suspension yield stress. The effect of key parameters such as solid volume fraction, suspension pH and ionic strength on the aggregate structure and hence the yield stress of the suspension was investigated. The results showed that the yield stress increased significantly under conditions that were favourable for formation of complex net-like aggregate structures, such as high solid volume fractions, pH values near the iso-electric point, and high ionic strengths. The suspension yield stress exhibited a power law dependency on the solid volume fraction. The interconnected network structure developed at high solid volume fractions was found to be the major contributing factor to the observed high suspension yield stress. A decrease in the number of bonds and the mechanical bonding strength of the aggregate structure was found to be responsible for the smaller suspension yield stress as the particle-particle repulsion becomes significant. Satisfactory agreement was obtained between simulation results and the published experimental data.
- Subject
- aggregate structure; coordination number; suspension yield stress; DEM
- Identifier
- http://hdl.handle.net/1959.13/1036660
- Identifier
- uon:13340
- Identifier
- ISBN:9780858259225
- Language
- eng
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