Initial growth kinetics and structure of colloidal aggregates in a turbulent coagulator

Population balance modeling of aggregation and breakage in turbulent Taylor–Couette flow

“…On the other hand, Saffman and Turner [38] obtained a similar value of the prefactor, equal to 1.293, for turbulent-flow conditions and spherical droplets. As was shown by Bäbler et al [39] once the hydrodynamic interactions of the particle on the surrounding fluid are incorporated in the trajectory analysis the value of aggregation rate prefactor reduces significantly, in agreement with experimentally determined values (see, e.g., [32,33,[40][41][42]). The reason for such differences from simple theoretical models is that the theoretical derivations did not include effects of particle interactions, such as hydrodynamic interactions, van der Waals attraction, surface chemistry, etc.…”

“…On the other hand, under conditions where the process is affected by shear the value of the fractal dimension increases and the aggregates are more compact. Specific examples of such experimental observations are for laminar shear flow [56], and for turbulent-flow conditions [16,42].…”

A study of the effect of drag-reducing surfactants on flow patterns in stirred vessels

“…In the present case, for the Mixel TT used, with a power number of Po = 0.74 (Aubin et al, 2001), for N = 5 Hz, ˙ = 365 s −1 , which is similar to the range of values published by Soos et al (2008) for a study in a vessel stirred by a Rushton turbine (Waldner et al, 2005). For this calculation, a value of = 1 mPa s is assumed for the viscosity of the stirred liquid; the Reynolds number for these conditions is calculated as Re = 45,125, i.e., the flow is definitely turbulent.…”

Effect of flow field heterogeneity in coagulators on aggregate size and structure

“…Two types of outer cylinder were used in the experiments, one made from stainless steel with several sampling ports, and the other from precision glass Duran from Schott (Mainz, Germany) used for flow field visualization with rheoscopic fluid. More details about the geometry of the coagulation units as well as on the characterization of the flow field through CFD can be found in Soos et al 17 for the TC-type devices, and Waldner et al 14 and Soos et al 46 for the ST, respectively. Characterization of Flow Conditions and Flow Field Visualization.…”