Flow properties of coagulated colloidal suspensions

Firth, Bruce; Hunter, Robert J.

doi:10.1016/0021-9797(76)90202-2

Cited by 208 publications

(45 citation statements)

References 16 publications

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“…They can, however, also be made to correspond to the collision efficiency of impermeable porous flocs by correcting the flow number for the fact that the attractive force between porous flocs is smaller than between solid particles. The only attractive interaction between two porous flocs which needs to be considered is that between the two nearest primary particles since the other particles in the two flocs are separated by too large a distance for the interaction forces to be effective (Firth and Hunter, 1976). Thus, the van der Waals attraction between porous flocs may be estimated by the force between two primary particles:…”

Section: Solid Particles and Impermeable Porous Flocsmentioning

confidence: 99%

Aggregation kinetics of small particles in agitated vessels

Kusters

Wijers

Thoenes

1997

Chemical Engineering Science

227

272

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Abstract--Rapid coagulation by turbulence in stirred tanks was studied for particles and aggregates smaller than the Kolmogorov microscale. The coagulation kinetics are determined by the floc structure and by the hydrodynamic and colloidal interactions between the colliding particles. The collision efficiency for doublet formation in the heterogeneous shear field of a stirred tank follows from particle trajectory analysis of solid particles in simple shear flow, provided the simple shear rate is made to correspond to the residence time weighted turbulent shear rate. Experimentally, the resulting aggregates proved to be fractal-like with their porosity increasing with aggregate size. Porosity within the aggregates results in penetration of the floc surface by the fluid flow, giving rise to enhanced collision efficiencies compared to solid particles. The collision efficiencies between porous flocs may be estimated by a model that pictures a porous floc as consisting of an impermeable core and a completely permeable shell. With the collision efficiencies from this shell-core model the aggregate growth could be described adequately.

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Section: Solid Particles and Impermeable Porous Flocsmentioning

confidence: 99%

Aggregation kinetics of small particles in agitated vessels

Kusters

Wijers

Thoenes

1997

Chemical Engineering Science

227

272

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“…Dans une série d'articles publiés dans les années 70, Hunter et ses collaborateurs [FIRTH et HUNTER, 1976 ; VAN DE VEN et HUNTER, 1977 ;HUNTER, 1982] cherchè-rent les paramètres qui auraient permis de corréler des données viscosimétriques pour des suspensions de particules rigides hydrophobes. Au moyen de quelques quantités, dont l'intérêt était considéré comme fondamental, ils proposèrent un modèle permettant de décrire le comportement quasi-binghamien (la figure 8 montre une courbe d'écoulement typique) de ces suspensions.…”

Section: Dimensions Des Agglomérats Et Structureunclassified

Quelques aspects rhéologiques des fluides colloïdaux

Schowalter

1989

La Houille Blanche

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“…In addition, the common plastic flow models that reasonably identify the non-Newtonian rheological flow behavior of paraffinic crudes at temperatures around and lower than the pour point are [13][14][15][16][17]: where: k 1 Casson yield parameter k 2 Casson viscosity parameter and…”

Section: Introductionmentioning

confidence: 99%

Low Temperature Rheological Behavior of Umbarka Waxy Crude and Influence of Flow Improver

El‐Gamal

Gad

1997

Rev. Inst. Fr. Pét.

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LOW TEMPERATURE RHEOLOGICAL BEHAVIOR OF UMBARKA WAXY CRUDE AND INFLUENCE OF FLOW IMPROVERThe low temperature flow properties; pour point and rheological parameters; have been determined for untreated and additive treated Umbarka waxy crude. The rheological characteristics of the crude showed non-Newtonian yield pseudoplastic flow behavior and pronounced thixotropic effect. Viscometric data are fitted to Bingham, Casson and Herschel-Bulkley plastic flow models using linear and non-linear computer regression analysis. Herschel parameters showed inconsistent results whereas Casson equation fitted the data reasonably well. Treatment of the crude with flow improver ameliorated both rheological properties and pour point but in a different manner. The influence of the additive on the rheology of the crude is greatly affected by shear rate. The thixotropic phenomenon of the crude is likely to be temperaturedependent in addition to the other controlling factors. El objeto de este estudio consiste en determinar las características del crudo parafínico de Umbarka, con o sin aditivos para la mejora de la fluencia, así como los datos reológicos. Las características reológicas del crudo presentan un comportamiento de fluencia seudoplástica, con un límite elástico no newtoniano, así como un efecto tixotrópico acusado. Se ha establecido una correlación entre los datos viscométricos y los modelos de fluencia plástica de Bingham, Casson y Herschel-Bulkley, utilizando para ello un análisis de regresión informática lineal y no lineal. Si bien los parámetros de Herschel dan lugar a resultados incoherentes, en cambio, la ecuación de Casson permite establecer una correlación razonablemente satisfactoria de los datos. El tratamiento del crudo por medio de un aditivo de mejora de la fluencia tiene repercusiones positivas, aun cuando diferentes, acerca de las propiedades reológicas y el punto de fluidez. Los efectos del aditivo sobre la reología del crudo dependen ampliamente de la relación del esfuerzo cortante y es probable que el fenómeno tixotrópico dependa de la temperatura, además de los otros factores determinantes.

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Flow properties of coagulated colloidal suspensions

Cited by 208 publications

References 16 publications

Aggregation kinetics of small particles in agitated vessels

Aggregation kinetics of small particles in agitated vessels

Quelques aspects rhéologiques des fluides colloïdaux

Low Temperature Rheological Behavior of Umbarka Waxy Crude and Influence of Flow Improver

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