Characterization of silicon-based ultrasonic nozzles

This paper presents the design and characterization of micro-fabricated 0.5 MHz silicon-based ultrasonic nozzles. Each nozzle is made of a piezoelectric drive section and a silicon-resonator consisting of five Fourier horns, each with half wavelength design and twice amplitude magnification. Results of impedance analysis and measurement of longitudinal vibration confirmed the simulation results with one pure longitudinal vibration mode at the resonant frequency in excellent agreement with the design value. Furthermore, at the resonant frequency, the measured longitudinal vibration amplitude gain at the nozzle tip of the 5-horn nozzle is in good agreement with the theoretical values of 25. Using this design, very high vibration amplitude gain at the nozzle tip can be achieved with no reduction in the tip cross sectional area for contact of liquid to be atomized. Therefore, the required electric drive power should be drastically reduced, thus avoiding transducer failure in ultrasonic atomization using the 5-horn ultrasonic nozzle.