On the structure of turbulent liquid—liquid dispersed flows in an agitated vessel

Study of drop and bubble sizes in a simulated mycelial fermentation broth of up to four phases

“…Increasing the oil content in the medium widened the size distribution, in particular increasing the size of the larger drops. Figure 7 shows that the Sauter mean diameter increased from 750 m for 2% oil to 1250 m for 15% oil as might be expected due to the increased coalescence (Davies, 1992;Pacek et al, 1994b). It is of interest to compare these sizes with those predicted from the work of Calabrese et al (1986) who suggested the following equation for agitation with Rushton turbines:…”

“…Once coalescence occurs at concentrations above about 1% v/v of the dispersed phase, the validity of the correlation becomes increasingly questionable (Pacek et al, 1998). If the dispersed phase is aqueous at a concentration of >20% v/v in the oil phase, the advanced video technique (noted earlier) has shown that droplets of the oil phase are also found inside the aqueous drops (Pacek et al, 1994b). If surfaceactive material is present, it affects both interfacial tension and coalescence behavior, and many types of such complex structures can form, and thus Eq.…”

Stirring and Stirred‐Tank Reactors

“…In general, for any given liquid-liquid system, the outcome is that in STRs, so-called high shea' Rushton turbines actually give larger drops than other impellers, even so-called low shear impellers such as the Chemineer HE3 (Fig. 5) [70].…”

“…The reason for this difference is not clear, but as a result, at the same volume fraction, A drops are bigger than O. At higher volume fractions, coalescence dominates so much that catastrophic phase inversion occurs and O/A dispersion becomes A/O, the transition always occurring at higher concentrations when oil is dispersed [70]. As a result of these complexities, prediction of phase inversion has also proven elusive.…”

Influence of a surfactant or salt on phase inversion in a water–oil pipe flow

“…Small parts of the continuous phase are trapped inside the dispersed phase. So the drops (forming the dispersed phase) grow, coalesce and finally form the new continuous phase (Pacek et al, 1994;Pacek and Nienow, 1995;Pal, 1993;Sajjadi et al, 2000Sajjadi et al, , 2002Sajjadi et al, , 2003Liu et al, 2005Liu et al, , 2006Jahanzad et al, 2009). • Dissipation rate.…”