The analysis of internal transient flow and the performance of valveless piezoelectric micropumps with planar diffuser/nozzles elements

Abstract

The influences of diverging angle, excitation frequency and volume change rate of the pump chamber on the valveless piezoelectric micropump with planar diffuser/nozzle elements are studied. The diverging angle ranges from 5° to 60°, the amplitude of the membrane ranges from 0.5 to 80 μm, the excitation frequency ranges from 10 to 5000 Hz. The deformation model of the membrane is verified by experiments. The performance of the micropump is predicted by numerical simulation. The simulation results agree with the experiment results very well. Statistical analysis of the location and duration of vortexes in internal flow field is used to reveal the relationships among efficiency, diverging angle, frequency and chamber volume change rate. As the frequency ranges from 100 to 1000 Hz, the efficiency increases sharply because the tube is partially blocked by vortexes at suction stage. The vortexes in the diffuser/nozzle elements is brought by the great adverse pressure gradient at the high frequency.