Flow measurements in a micromachined flow system with integrated acoustic pumping

In this paper a general scheme for the realization of micromachined flow systems with integrated fluid pumping is introduced. Microscopic channels are formed at the interface between an etched glass cap and a silicon micromachined flexural plate wave (FPW) device. The FPWs excite an acoustic field in the fluid that occupies the channel, and the acoustic field in turn drives fluid flow. The flow driving mechanism is acoustic streaming, a nonlinear acoustic phenomenon in which a finite-amplitude acoustic field sets the host fluid into motion. A scheme for the realization of such flow systems is outlined and a simple microflow system that implements this scheme is fabricated and tested