Design, fabrication, and mixing characteristics of an electrostatically activated resonant micropump-mixer

An active mixing and pumping strategy is proposed to enhance mixing of two fluids through vortex accumulation by a resonant plate actuation. A resonant micropump-mixer is designed and fabricated, where an electrostatically activated plate is placed at or in close vicinity of the interface between the two incoming streams at the junction of a Y-shaped microchannel. Mixing is enhanced by increased interface area between the two fluids during the vortex formation at the tip of the resonant plate. Fabrication of the micropump-mixer is achieved in two steps. Commercial PolyMUMPs process is initially used to fabricate a resonant plate, where it is eventually packaged into a Y-shaped microchannel. The resonant plate, in this study, has a length of 300 μm, thickness of 1.5 μm, and it is activated by an AC power source, which results in significant oscillation amplitude at the tip of the plate. The Laser Induced Fluorescence (LIF) technique is used for flow visualization and characterization, where effective mixing and pumping capabilities of the micropump-mixer are demonstrated.