Dissecting liquid-liquid dispersions
15 Jan 2000
Understanding the complex behaviour of two phase liquid-liquid dispersions requires good measuring techniques. As part of an EPSRC/DTI Link project with Zeneca, BHR Group and Unilever, Andrzej Pacek and Alvin Nienow have developed a novel video method.
The system employs a stereo-microscope, a high resolution video camera and a high intensity strobe light. It measures drop sizes down to 20 m at concentrations up to phase inversion. Bubbles can be distinguished from oil drops, as can solids, and entities as small as 5 m can be observed.
Pacek calls the system's combination of features 'a quantum improvement in our understanding of the dynamics of high phase fraction dispersions'.
Directly sponsored work has been commissioned by ICI on the spatial distribution of drops and bubbles in a stirred vessel; by BNFL to look at aqueous-organic waste material during processing; and by Chemineer for studying the mechanism of break-up of high viscosity oils in static mixers.
