Agglomerates rupture

Illustration Kinetics of dispersion the two-zone model. The models for agglomerate rupture when integrated with a flow model are useful for the modeling of dispersion in practical mixers, as was discussed for the case of drop dispersion. Manas-Zloczower, Nir, and Tadmor (1982), in an early study, presented a model for the dispersion of carbon black in rubber in a Banbury mixer (Fig. 34). The model is based on several simplifying assumptions Fragmentation is assumed to occur by rupture alone, and each rupture produces two equal-sized fragments. Rupture is assumed to occur... 

Manas-Zloczower, I., Nir, A., and Tadmor, Z., Dispersive mixing in internal mixers—a theoretical model based on agglomerate rupture. Rubber Chem. Tech 55, 1250-1285 (1982). 

I. Manas-Zloczower, A. Nir, and Z. Tadmor, Dispersive Mixing in Internal Mixers - A Theoretical Model Based on Agglomerate Rupture, Rubber Chem. Technol., 55, 1250-1285 (1982). 

Models have also been developed to analyse the dispersibility of ellipsoidal clusters [13] and the relative effects of different flow geometries, from which biaxial extension was found to be most efficient in influencing particle rupture [14,15]. Furthermore, although it is generally assumed that in the agglomerate rupture process the parent agglomerate produces two identical fragments, controlled experimental studies have also been... 

Agglomerates in a sheared fluid rupture when the hydrodynamic stress exceeds a critical value in dimensionless form the criterion for rupture is Fa > Facrjt. Rupture occurs within a short time of application of the critical stress, and thus can be distinguished from erosion, which occurs over much longer time scales. 

Rupture of fractal (flocculated) aggregates of polystyrene latices in simple shear flow and converging flow was studied by Sonntag and Russel (1986, 1987b). For simple shear flow and low electrolyte concentrations, the critical fragmentation number decreases sharply with agglomerate radius (R) as... 

A model has been developed to describe the penetration of polydimethylsi-loxane (PDMS) into silica agglomerates [120]. The kinetics of this process depend on agglomerate size and porosity, together with fluid viscosity. Shearing experiments demonstrated that rupture and erosion break-up mechanisms occurred, and that agglomerates which were penetrated by polymer were less readily dispersed than dry clusters. This was attributed to the formation of a network between sihca aggregates and penetrated PDMS, which could deform prior to rupture, thereby inhibiting dispersion. 

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