Micro-mixing system with piezoelectric pumping mechanism

Abstract

MicroMixing Systems (MMS) have gained increasing attention recently due to the device downscaling trend from academic research apparatus to commercially available products. They play a critical role in fields such as electronics, renewable energy, and biological engineering.

In general, MMS can be divided into two components: micromixers and pumps. Extensive research has been carried out in development of these components. However, we found that piezoelectric pumps, common in other microscale systems, are rarely used in micromixers. Their advantages in small size, high flow rate, and easy fabrication method make them promising in improving the overall performance of MMS.

Thus in this project, we built a prototype of an MMS with a piezoelectric pump. The optimal working condition and pumping performance was tested through a series of experiments. Experiment results proved the workability of the prototype. At 40 V and 340 Hz, the PZT MMS had a maximum flow rate of 2μl/s, which is higher than other pumping mechanisms. Due to the controlled fluid behavior before the mixing region, there was no backflow or premature mixing. The size of the prototype is considerably small, and yet has great potential for size reduction because of the design. The fabrication process is also much simpler than most of other MMS.

However, the piezoelectric pumping mechanism also has some limitations. Future improvements need to be made in the mechanical property of PZT ceramics, flow rate control, and portable power supplies.