Comparative Study of State‐of‐the‐Art Micromixers: Mixing Efficiency and Design Recommendations

The mixing efficiency of five micromixer geometries, such as Butterfly, Baffle, Stretch–Split–Recombine, Staggered Herringbone Mixer, and Serpentine micromixer, is assessed using computational fluid dynamics (CFD) over a Reynolds‐number ( Re ) range from 1 to 180. Additional dye tracer experiments, using confocal microscopy, validate the CFD findings in the case of the Serpentine mixer, considering two homothetic sizes (100 × 100 and 200 × 200 µm) and Re = 50 and 180. Although all micromixers achieve high mixing efficiencies, their characteristic mixing times span more than four orders of magnitude (0.249 ms to 2.82 s), depending strongly on geometry and flow regime. This wide dynamic range indicates that mixing performance is governed not only by Reynolds number but by the underlying transport mechanism vortex‐driven convection versus topological stretching and reorientation. Geometries based on systematic splitting and chaotic advection maintain short mixing lengths even at high Péclet numbers, whereas residence time depends on absolute geometric scale and operating flow rate. The results show that mixer selection should be guided not only by Reynolds number but by the desired mixing time, flow rate, pressure constraints, and fabrication complexity. These findings provide practical design guidelines and a scalable framework for micromixer selection in continuous‐flow synthesis.