Drop sizes in turbulent liquid–liquid dispersions containing polymeric suspension stabilizers. I. The breakage mechanism

Polymeric suspension stabilizers, when used in sufficient quantities, can stabilize liquid–liquid dispersions against coalescence. Experiments were performed using an in situ photomicrographic technique to determine the critical surface coverage of a hydroxypropyl methylcellulose product. The critical surface coverage was between 2.35 × 10−7 and 1.2 × 10−6 g/cm2. Noncoalescing dispersions can be prepared by using high concentrations of suspending agents so that the surface coverage is above the critical value. Such noncoalescing dispersions can be used to study the breakage mechanism even at high dispersed phase volume fractions. The study of the breakage mechanism reveals that the volume swept by the turbine impeller is applicable in calculating the power input per unit mass. The new correlation between the Sauter mean diameter and the extent of agitation under turbulent conditions that is found here is in fair agreement with those available in literature.