Dynamic analysis of piezoelectric valveless micropumps: Effects of piezoelectric transducer material

Dynamic structural and fluid flow analysis of bulk acoustic wave piezoelectric valveless micropumps are carried out for the transport of water. The micropumps consist of trapezoidal prism inlet/outlet elements; the pump chamber, a thin structural layer (Pyrex glass) and a piezoelectric transducer element (PZT-5A, PZT-4, or BaTiO₃), as the actuator. Flow contraction and expansion, through the trapezoidal prism inlet and outlet respectively, generates net fluid flow. Governing equations for the flow fields and the structural-piezoelectric bi-layer membrane motions are considered. For the compressible flow formulation, an isothermal equation of state for the working fluid is employed. Two-way dynamic coupling of forces and displacements between the solid and the liquid domains in the systems are considered where actuator deflection and motion causes fluid flow and vice-versa. 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.