Electrocoalescence of drops in a water-in-oil emulsion

摘要

Electrocoalescence of water drops in a stagnant water-in-oil emulsion has been studied in a newly developed test cell. An homogeneous electric field was applied across the emulsion volume. It was used to observe drop behaviour in a multi-drop system. The emulsion was made of napthenic oil containing chemically stabilized water drops with size in the range of 5–100 μιη. Insulated electrodes were used to prevent direct charge injection and electrophoresis. Drop dynamics in the stagnant emulsion was observed by use of a high speed optical camera and high resolution optics. Three parameters were varied systematically: water cut, frequency and amplitude of the bipolar square voltage. Different events during electrocoalescence are described and discussed, including dynamics of both collapse and break-up of drops, chain formation and charge transfer in the emulsion.