Effect and Evaluation of an Ultrasonic Atomizer With Large Vibration Amplitude

An ultrasonic atomizer can produce large vibration amplitude is
designed. Different from the structure of the usually seen ultrasonic
spray nozzle, the atomizer is fundamentally constructed with a hollow tube encircled with several pieces of sectional type piezoelectric
actuators, which can radially oscillate the tube to generate desired
vibration profile. Atomization is formed on the surface around the
liquid outlet of the tube where maximum vibration amplitude
occurs. In search of resonance frequency and vibration amplitude,
modal and harmonic analyses of the ultrasonic atomizer are carried
out by ANSYS. In comparison the simulated results with the experimental results, both are in good agreement. A measurement system
is set up for detecting the atomization droplets and calculating the
droplet size and distribution. An attempt is to design an ultrasonic
atomizer can produce high distribution and small diameter droplets
for some application-level requirements, droplet diameter around
20�60 lm is assumed to be the specification for performance verification of the proposed atomizer. In experiment, it is found nearly
90% of atomized droplets fit for the requirement. Besides the most
important factor of operating frequency, a relation of amplitude is
found to include in the well-known Lang and Rayleigh�s equation.