Flow profiling of a surface acoustic wave nanopump

TL;DR

This study investigates the flow profile and efficiency of a surface acoustic wave nanopump using experimental and theoretical methods, revealing how acoustic streaming depends on power and distance from the generator.

Contribution

It provides new insights into the flow dynamics and efficiency of surface acoustic wave nanopumps through combined experimental and theoretical analysis.

Findings

Flow velocity depends weakly on power

Flow velocity decreases rapidly with distance from the ultrasound source

Acoustic streaming can be used for controlled microfluidic agitation

Abstract

The flow profile in a capillary gap and the pumping efficiency of an acoustic micropump employing Surface Acoustic Waves is investigated both experimentally and theoretically. Such ultrasonic surface waves on a piezoelectric substrate strongly couple to a thin liquid layer and generate an internal streaming within the fluid. Such acoustic streaming can be used for controlled agitation during, e.g., microarray hybridization. We use fluorescence correlation spectroscopy and fluorescence microscopy as complementary tools to investigate the resulting flow profile. The velocity was found to depend on the applied power somewhat weaker than linearly and to decrease fast with the distance from the ultrasound generator on the chip.