A novel valve-less piezoelectric micropump generating recirculating flow

Abstract

Microfluidic devices or systems to generate recirculating flow are increasingly utilized in the fields of chemistry, biomedicine, biology, with bottlenecks in integration and miniaturization needed a breakthrough. Here, a concept for a highly integrated valve-less piezoelectric micropump generating recirculating flow (VPMGRF) is proposed, simultaneously realizing innovation in theory and method. Based on fluid inertiaand energy dissipation of vortexes, a novel double-loop tube was designed to achieve fluid flow in different directions along various paths, with the flow characteristics at different cross-sectional areas explored through computational fluid dynamics (CFD). Afterwards, as valve bodies, the double-loop tubes were connected with a piezoelectric-actuated chamber to constitute the VPMGRF, which was followed by establishing a theoretical model of the vibration, fluid dynamics, and net flow rate. Eventually, experimental results showed that VPMGRFs could generate internal recirculating flow and had a pump effect. The maximum net flow rate reached 5.19 mL/min at 8 Hz, corresponding to a vibrator amplitude of 35 μm and an output pressure amplitude of 4.27 kPa. Furthermore, the larger the characteristic length of the cross section, the greater the amplitude of the vibrators, the larger the amplitude of output pressure, and the slower the flow rate.

Working Mechanisms and Experimental Research of Piezoelectric Pump with a Cardiac Valve-like Structure

“…Pumps are considered powerful methods through which human beings to understand and transform the world [ 2 , 3 , 4 ]. Traditional pumps are driven by electric machinery; their disadvantages are their large volume, high power consumption, and lack of electromagnetic interference, which hinders their application in microfluidic and other fields [ 5 , 6 , 7 ]. With the development of the micro-electro-mechanical system (MEMS), micro pumps such as electrostatic pumps [ 8 , 9 ], thermally driven pumps [ 10 , 11 ], and piezoelectric pumps [ 12 , 13 ] have attracted wide attention.…”

“…Generally, the fluid is driven by the piezoelectric pump through the piezoelectric vibrator and special structures. It has the advantages of a simple structure [ 15 ], easy miniaturization [ 16 ], and no electromagnetic interference [ 17 ], leading to widespread use in microfluidic applications [ 5 , 6 , 7 ], medical equipment [ 18 , 19 , 20 ], fuel cells [ 21 , 22 , 23 ], and other fields. In terms of structure, piezoelectric pumps can be divided into valve-based piezoelectric pumps and valve-less piezoelectric pump [ 13 ].…”