Modeling and experimental validation of a piezoelectric micropump with novel no-moving-part valves

Abstract

No-moving-part (NMP) valves are microconduits able to partially rectify an oscillating fluid moving through them. The modeling of such valves is not at all trivial. Even greater difficulties arise when the behavior of the whole micropump equipped with those NMP valves is investigated, because of the complex fluid-dynamic phenomena interacting with deformable structures. This paper proposes a generalization of the efficiency modeling, nowadays used for single valves, to whole micropump equipped with them. Such modeling has been applied to design a novel, high efficiency NMP valve to be used in a piezoelectric micropump. The main feature of the new valve is the presence of some properly shaped vortex area along its fluid-dynamic pattern, allowing to improve micropump performance. For comparison purposes, the same modeling has been applied to a standard nozzle-diffuser NMP valve to be used with the same piezoelectric actuator. The experimental comparison of micropump performance (maximum flow rate and pressure head) shows that the proposed modeling technique is able to discriminate between better and worse performer. The effects of unsteady dynamic effects have been evaluated a posteriori, confirming their important weight on the actual performance of the micropumps equipped with NMP valves.