Three dimensional co-axial defocusing flow-assisted micro-mixing for enhanced molecular diffusion

We proposeda passive micro-mixer using three dimensional co-axial defocusing flows. A computer-aid simulation was performed to optimize the design of the micro-mixer. Based on the simulated results, the micro-mixer was fabricated with two glass capillaries which could provide a true three dimensional geometry. The micro-mixer was tested with Rhodamine B dye for visualization. The results showed that defocusing flow was gradually developed below 3,000 μ/h at low concentration (0.5 mol/m³) of Rhodamine B and below 6,000 μl/h at high concentration (2.0 mol/m³). Molecular diffusion could be enhanced with high concentration and defocusing flow at low water flow rate, resulting in a possible passive micro-mixing.