• fluid dynamics
• Static mixer
• PLIF
• mixing
• emulsion

The performance of Kenics (KM) and Sulzer (SMX+) designs of static mixer has been investigated for the mixing of immiscible fluids using in situ optical measurements. The fluids used are water as the continuous phase and either silicone oil in the presence of surfactant (Sodium Lauryl Ether Sulfate), or Lytol mineral oil in the presence of a nonionic surfactant (Span 80). The dispersed phase volume fraction was between 0.0072% and 0.028 % and the superficial velocities ranged from 0.16 to 0.91 m/s.
The pipe diameter was 0.0127 m and 6 or 12 mixing elements were used for each mixer type. Planar Laser Induced Fluorescence (PLIF) has been used to obtain images of the droplets formed in a traverse section across the mixer outlet. Image analysis methods have been developed, based upon the areal distribution and individual striation methods proposed by Alberini et al. (2014a, 2014b) for the blending of miscible fluids. The analysis enables drop size distributions to be obtained as a function of the number of mixing elements, interfacial tension and superficial velocity.
A model for the drop size distribution has been developed in order to predict mixer performance a priori.