Tri-fluid mixing in a microchannel for nanoparticle synthesis

Area of Science:

• Fluid Dynamics
• Microfluidics
• Nanotechnology

Background:

• Multi-reactant processes like continuous-flow reactions and nanoparticle synthesis face challenges with traditional bulk and bi-fluid micromixing.
• Micromixing research has predominantly focused on two-fluid systems, neglecting the complexities of multi-fluid mixing.

Purpose of the Study:

• To investigate and compare tri-fluid mixing efficiencies in different microchannel geometries.
• To develop an effective method for mixing three fluids simultaneously in microchannels for advanced synthesis applications.

Main Methods:

• Numerical simulations and experimental validation were employed to analyze tri-fluid mixing.
• Three microchannel designs were evaluated: straight, staggered herringbone mixing (SHM), and a 3D X-crossing channel.
• A two-step experimental process assessed mixing performance across various Reynolds numbers (Re).

Main Results:

• The SHM microchannel showed limited enhancement for tri-fluid mixing, especially at Re > 10.
• The 3D X-crossing microchannel, utilizing splitting-and-recombination (SAR), demonstrated efficient tri-mixing over a broad Re range (up to 275).
• SAR-based tri-fluid mixing enabled high microchannel throughput and was successfully applied to synthesize Si-based nanoparticles with a narrower size distribution.

Conclusions:

• The 3D X-crossing microchannel with SAR is highly effective for tri-fluid mixing, offering superior performance to SHM.
• This SAR-based tri-fluid micromixing technique provides a viable alternative for multi-reactant chemical and biochemical processes.
• The method facilitates efficient nanoparticle synthesis, improving product uniformity.