A computational study on transducer material selection in bulk acoustic wave piezoelectric valveless micropumps

A bulk acoustic wave piezoelectric valveless micropump consisting of trapezoidal prism inlet/outlet elements; the pump chamber, a thin structural layer and a piezoelectric transducer element, as the actuator is investigated. Dynamic structural and fluid flow analysis of the micropump are carried out for the transport of water. Governing equations for the flow fields and the structural-piezoelectric bi-layer membrane motions are considered. Flow contraction and expansion, through the trapezoidal prism inlet and outlet respectively, generates net fluid flow in the investigated micropump. The effects of the piezoelectric transducer material on the flow rate are investigated for several commonly used actuators: PZT-5A, PZT-4, and BaTiO₃ . The net flow rate developed by the pump varies with the piezoelectric material. PZT-5A actuator generates the largest pump net flow, and the BaTiO₃ actuator results in the lowest pump flow. The findings imply that PZT-5A as the micropump actuator is advantageous to generate a high pump flow. In some applications where pumping precision is important BaTiO₃ should be the material of choose. Comparison of the pumping characteristics of the micropumps operating with different piezoelectric transducer materials can be utilized to design MEMS based micropumps in drug delivery and biomedical applications especially if lead contamination originating from PZT has to be avoided such as in vivo applications.