• multiphase mixing;
  • surfactants;
  • liquid–liquid dispersion;
  • jet breakup;
  • hydrodynamics


The contacting of multiple liquid phases is a complex process; and one that is often difficult to study experimentally. However, many multiphase mixers function by forcing an immiscible fluid through an orifice or nozzle, which can be modelled using an axisymmetric jet. Despite the extensive literature on jets, there is little information on the role played by surfactants in determining jet breakup length and drop diameter.

Experiments involving the discharge of oil jets into otherwise quiescent aqueous surfactant solutions were performed over a broad range of conditions. Jet length was found to increase with surfactant concentration, while droplet diameter was found to decrease (dependent on jet regime). These results compare favourably with, and can aid the interpretation of similar experiments in high shear mixers.