Abstract: An ultrasonic micromixer consisting of a mixing chamber of 6 mm diameter and 60 μm high, a 210 μm thick lead-zirconate-titanate (PZT) actuator and four 2 cm vertical tubes, is fabricated for experimental research. The resonant modes of the diaphragm are computed and the error is analyzed. A microfluid flow field characterization is performed with particle image velocity (PIV) by using a laser scanning convex microscope. The vortices and the particle focuses along the boundary of the flow field within the chamber are observed; and hydraulic pressure difference and the relation between the difference and driving voltage across the ultrasonic transducer are obtained when the micromixer works in its first order mode.

Key words: Microfluidics, Micromixer, Particle image velocimetry, Ultrasonic driving