The development of a valveless piezoelectric micropump

Previous studies have indicated that the performance of the micropump is influenced by the driving voltage, frequency, valves, and pump chambers. In this study, an innovative one-side actuating valveless micropump is proposed and developed to actuate liquid in one direction with high flow rates and pump heads. The three-dimensional, transition numerical models of the micropumps were also employed to predict its performance. It was found that the inlet choking phenomenon was the major reason to make the one-side actuating micropump valve-free, with a flow rate of 0.088 mL/s and a pump head of 45.6 Pa. By adding the secondary chamber, the performance can be improved to 0.989 mL/s and 1291.0 Pa. The maximum pump head in this study was obtained at 1522.5 Pa by using the 0.3-mm-thick secondary diaphragm. In addition, the performance of the micropump can be further improved by adding a nozzle/diffuser element, thus enabling it to achieve the maximum flow rate of 1.133 mL/s at the frequency of 150 Hz. Without additional check valves, the one-side actuating piezoelectric valveless micropump with compact design can perform more accurately and reliably in the applications of biomedical and electronics cooling.