The production of uniform-sized nanoparticles has potential application in a wide variety of fields, but is still a challenge. One main reason that many lab-scale manufactured nanoparticles have not appeared in industry is because there is lack of control on physical properties and surface functionality of nanoparticles during massive production. Recently, a process called "Flash Nanoprecipitation (FNP)" has been developed to produce nanoparticles with controlled size and high drug-loading rate. In FNP, fast mixing is required to make sure that solvent and non-solvent mix homogeneously so that competitive precipitation of organics and polymer could result in functional nanoparticles with narrow size distribution. A multi-inlet vortex reactor (MIVR) has been developed to provide fast mixing for the FNP. The MIVR includes four inlets which are tangential to the mixing chamber of reactor. The MIVR has the operational advantage of providing different inlet-flow momentum and configurations compared to other reactors used in the FNP such as confined impinging jet reactor (CIJR). Former studies have already shown its ability of providing fast mixing and successfully producing functional nanoparticles in the FNP. However, until now all previous investigations about the MIVR only focused in its micro-scale (dimensions in millimetre).

While the micro-scale MIVR does show great promise in the production of functional nanoparticles, the small dimensions and correspondingly small output of the micro-scale MIVR limit its usefulness to producing functional nanopraticles for applications requiring small production run such as high-value pharmaceutical agents. Some applications such as nanoparticle used in pesticides and cosmetics may require larger production run than the micro-scale MIVR can provide, making it economically unrealistic based on the relatively high capital and operating costs needed for a large number of reactors operating in parallel. For this reason, in the study we are interested in investigating the feasibility of scaling up the FNP process to a macro-scale MIVR capable of generating large quantities of functional nanoparticles, both rapidly and economically, and consequently developing experimentally verified computational fluid dynamics (CFD) models that can be used as design tools for further optimizing reactor design and operation parameters to produce customized functional nanoparticles. To accomplish this investigation, a macro-scale MIVR has been built with optical access. Non-intrusive, optical-based measurement techniques including particle image velocimetry (PIV) and planar laser-induced fluorescence (PLIF) were used to measure flow field and mixing, and related CFD models, specifically turbulence models were validated and developed for optimizing the MIVR and future model development of the FNP process.