Enhanced flow control in electromechanically driven valveless micropumps: from structural design insights to multi-core actuation dynamics

This study presents a fully cylindrical piezoelectric micropump for precise fluid handling in microfluidic applications. The design integrates a ring-shaped piezoelectric actuator with a flexible membrane above a cylindrical fluid chamber. Under sinusoidal actuation, the actuator induces vertical membrane oscillations that generate pressure gradients, and drive directional fluid transport. Simulation results show that applying a 0.2V/μm electric field yields an accumulated flow volume of 1.3197μL per cycle, with peak inlet and outlet flow rates reaching approximately 0.038mL/s. Parametric analyses reveal that increasing the number of piezoelectric layers at constant voltage, significantly boosts flow rates due to enhanced mechanical stiffness and actuation force. Additionally, expanding the inner radius of the actuator improves membrane leverage and peak displacement. In contrast, increasing the outer radius distributes force over a larger area, which enhances net volume flow despite reduced peak deflection. Larger membrane radii amplify volumetric displacement through increased surface area. However, enlarging inlet/outlet port radii reduces flow rates due to diminished pressure buildup and weakened passive flow rectification. Frequency sweep analysis identifies a resonant frequency at 940Hz, where maximum flow of 4.1528μL is achieved. Furthermore, multi-core actuator configurations composed of several narrower piezoelectric rings, demonstrate tunable pumping characteristics that depend on their spatial arrangement. These findings underscore the importance of geometric and electrical optimization in piezoelectric micropump design. They provide a robust framework for enhancing performance and controllability in precise microfluidic applications.