A piezoelectric pump with flow-concentrating chamber for multifunctional microfluidic systems.

Piezoelectric pumps have garnered significant interest in such systems owing to their compact form factor, ease of integration, rapid response, and precise fluid delivery. However, simultaneously achieving high output and stable flow remains challenging due to internal flow losses and flow field fluctuations. To overcome this limitation, we propose a piezoelectric pump with a flow-concentrating chamber (PPFC) for multifunctional microfluidic applications. The flow-concentrating chamber creates a low-resistance pathway within the pump chamber, which regulates hydraulic resistance distribution and enhances directional fluid transport. The performance of the PPFC was systematically characterized through numerical simulations, prototype fabrication, and experimental measurements, including on-chip particle tracking velocimetry (PTV). Compared with a standard piezoelectric pump, the PPFC achieved an approximately 30% higher output flow rate and a significant reduction in velocity fluctuation, demonstrating improved pumping efficiency and flow stability. Furthermore, the PPFC was successfully applied to droplet generation and inertial particle focusing, exhibiting performance comparable to that of conventional constant-flow pumping systems. This work provides a simple and scalable strategy for improving the performance of piezoelectric pumps and advancing their integration into multifunctional lab-on-a-chip platforms.