Coupled multifield analysis of piezoelectrically actuated valveless-micropump MEMS devices are carried out for liquid transport applications. We consider the three-way coupling between electrical, mechanical and fluidic fields in such systems where actuator deflection causes fluid flow through a micropump. Flow contraction and expansion (through a nozzle and a diffuser respectively) generates net fluid flow as the bilayer structural-piezoelectric membrane of the actuator deflects. The analysis involves structural and fluid field couplings in a sequential structural-fluid analysis of the microfluidic device. The effect of the driving voltage on silicon-PZT-5A membrane deflection and flow rate through the inlet/outlet is investigated via time averaging the predicted instantaneous velocity fields. At low actuation frequencies (below 10 kHz), the excitation voltage is a dominant factor on the flow rate of the micropump. The pressure, velocity and flow rate prediction models developed in the present study can be utilized to optimize the design of MEMS based micropumps.

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