MEASUREMENT OF DROP SIZE DISTRIBUTION IN CONCENTRATED LIQUID-LIQUID DISPERSIONS - VIDEO AND CAPILLARY TECHNIQUES

Distributions in a concentrated dispersion have been measured in a sti rred vessel. With the capillary technique, with a wide distribution, e ven after extensive testing of different sized capillaries and entry c onditions and of threshold levels, both ends of the distribution were cut off. Sampling time is a problem when studying fast transients, as is the amount of fluid withdrawn when investigating phase inversion. P rovided pictures can be taken, the video technique allows droplets fro m 25 mu m upwards at concentrations up to those which cause phase inve rsion, i.e. similar to 70% by volume dispersed phase, to be observed. These observations can be made at the wall and, by means of a 7 mm dia meter 'light pipe' and similar sized optical fibre strobe, inside the vessel. With a framing rate of 50 per second, the technique gives, sec ond-by-second, size distributions to any discretization and means to a ny base. The structure is also revealed; for example, droplets-in-drop s and bubbles are distinguishable from drops.