Abstract：To investigate the output performance of valveless piezoelectric micropumps under the influence of multifield coupling, a numerical simulation method was proposed. The valveless piezoelectric micropumps with wall attached jet was taken as the object for numerical calculation. Experiments were used to verify the feasibility of numerical simulation and the output performance of the pumps were investigated. The results show that the flow rate and back pressure of the pumps first increase and then decrease with the increase of frequency. When the micropump is driven with a voltage of 200 V at 62.5 Hz, the maximum flow rate and the back pressure were 0.703 mL/min and 0672 kPa, respectively. The displacement distribution of the piezoelectric vibrator and the instantaneous flow rate of the piezoelectric pump were extracted.It was shown that the reason why the instantaneous flow rate of the outlet of the piezoelectric pump lags behind the voltage was due to the influence of the coupling effect. The flow rate of the pumps both increase first and then decrease with the increase of the height of throat H. When the micropump is driven with a voltage of 200 V at 50 Hz, the maximum flow rate reaches 4.023 mL/min with H=0.4 mm. Combined with maximum instantaneous displacement curve of piezoelectric vibrator and flow field vector, it was shown that the maximum amplitude of the piezoelectric 〖JP2〗vibrator was determined by the total flow from the pump chamber, and the size and position of the vortex was formed in the internal flow field, which determine the flow distribution between the inlet and outlet.
