The micro-Particle Image Velocimetry (micro-PIV) was used to measure flow velocities in micro-channels

in two passive micromixers: a microfluidic Venturi mixer and a microfluidic spiral mixer, both preceded

by standard “Y” micromixers. The micro-devices were made of borosilicate glass, with micro-engineering

techniques dedicated to micro-PIV measurements. The obtained velocity profiles show differences in the

flow structure in both cases. The micro-PIV enables understanding the micro-flow phenomena and can help

to increase reproducibility of micromixers in mass production.