Development of a valveless piezoelectric pump with vortex diodes

The cut-off capacity of the fluid diode determines the output performance of the valveless piezoelectric pump with flow resistance difference tubes. In this study, a valveless piezoelectric pump with vortex diodes is proposed, which utilizes the vortex diodes as internal valves with no moving parts. The internal flow field is calculated for the vortex diode with different chamber diameter ratios. The largest impedance ratio of the structural parameters of the vortex diode is obtained from the calculation results. Then, different prototypes of the piezoelectric pumps with a diffuser/nozzle, Tesla tubes and vortex diodes are manufactured. The experimental results demonstrate that the output performance of the valveless piezoelectric pump with vortex diodes is better than those of the other pumps: the maximum flow rate of the valveless piezoelectric pump with vortex diodes reaches 9.86 g min⁻¹ at a driving voltage of 200 V with a driving frequency of 49 Hz, and the maximum output pressure of the piezoelectric pump reaches 340 Pa. In addition, the valveless piezoelectric pump with vortex diodes achieves a good carrying capacity, which is suitable for transmission of high-viscosity liquid. Flow field analysis demonstrates that strong vortex motion and strong shear forces exist near the center of the vortex chamber, which provide the basis function for fluid mixing and fluid separation. (paper)