Characterization of mixing in a coaxial jet mixer for nanoparticle fabrication

Abstract

Mixing in a micro-scale coaxial turbulent jet mixer for the fabrication of nanoparticles for drug delivery was experimentally characterized. Rapid mixing due to turbulence offers improved control of nanoparticle production over conventional bulk nanoprecipitation methods. Mixing time was determined based on photographs of mixing of an acidic solution and a basic solution in the device, with phenolphtalein used as an indicator of the extent of mixing. The average Reynolds number and velocity ratio were varied. The velocity ratio varied between 0.1 and 10. The Reynolds number varied between 200 and 1800. Mixing times on the order of 1 to 50 ms were measured in the device. The mixing time was found to be proportional to average velocity to the -3/2 power. The data showed some agreement with predicted mixing time based on the EDD model for turbulent micromixing in the jetting regime.