An Active Micromixer Based on Reverse Piezoelectricity Effect
In this study, we used a piezoelectric bimorph actuator (model no. T220-A4-503X. Piezo systems, INC.), which is composed of three layers (pzt-copper-pzt) and can provide very large reverse-piezoelectric deformation (on the order of micrometers). This deformation is directly used to induce fluid motion in the microchannel for mixing enhancement. To do so, the piezoelectric actuator was glued to the top wall of a shallow chamber, which is connected to the main mixing channel through a converging nozzle. The deformation of piezo (together with the soft top wall of the chamber) induces volume change of the chamber, which results in very strong in/out flow at the nozzle. This oscillatory in/out flow shows great promise in enhancing mixing in the channel.
The preliminary results show that fluid mixing was remarkably promoted by the reverse piezoelectricity effect. Further optimization was deemed necessary to understand the effect of the reverse piezoelectricity, driving frequency, the driving voltage and the flow rates on mixing performance. Overall, our experiments demonstrate that reverse piezoelectricity effect facilitates simple and an inexpensive way to rapidly and homogenously mix fluid in a microchannel.
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