Theoretical and experimental research of caudal-fin-type piezoelectric-stack pump with variable-cross-section oscillating vibrato

In this paper, a piezoelectric-stack pump with variable-cross-section oscillating (VCSO) vibrator is proposed, which imitates the swing of the caudal-fin of tuna, and the pump is neither the rotating type nor the volumetric type according to the taxonomy. The interaction between the oscillating vibrator and the fluid parcel is firstly analyzed from the viewpoint of momentum conservation, and the analytical expression of pump flow rate is obtained. At last, experimental measurement for the flow rates with different driving frequencies is conducted. The results show that the flow rate can reach 560 ml/min at 1370 Hz when the pump runs under the backpressure of 30 mm water column. And the flow rate is as much as 560% of that of experiment results carried out by Cícero R. De Limaa. The proposed pump innovates in both theory and taxonomy. In addition, the pump overcomes the drawbacks such as large flow fluctuation and low flow rate in the traditional FRD type pumps, which will help to broaden the applications of the valve-less piezoelectric pump.