Characterization of liquid and gaseous micro- and nanojets using microcantilever sensors

This paper reports the development of microelectromechanical metrology tools to characterize liquid and gaseous jets generated from microfabricated nozzles with diameters ranging from 1 to 12 μm. Microcantilever sensors with either piezoresistive elements or integrated heating elements have been fabricated and applied to measure thrusts, velocities, and heat transfer characteristics of micro/nanojets. Piezoresistive cantilever measurements showed that liquid butane microjets from a 6 μm diameter nozzle achieved velocities 40–60 m/s for driving pressures 0.6–1.4 MPa. Jet velocities estimated from cantilever measurements agreed well with shadowgraphy results within 12.5% without any correction factor. A microcantilever with integrated heating elements measured cooling capacities of liquid butane microjets on the order of 10−5 W/K.