Design Analysis for Controlling Spray Particle Size of Ultrasonic Nozzles Using Piezoelectric Ceramic Vibrators.

Area of Science:

• Materials Science
• Mechanical Engineering
• Fluid Dynamics

Background:

• Industrial spray nozzle design requires precise control over particle size.
• Ultrasonic atomization offers a promising method for achieving fine and uniform droplets.
• Piezoelectric ceramics are key components in ultrasonic transducers for spray generation.

Purpose of the Study:

• To demonstrate the feasibility of controlling particle size via a mathematical model for ultrasonic spray nozzles.
• To design and fabricate an ultrasonic nozzle capable of producing ~30 μm particles for industrial use.
• To analyze the relationship between nozzle design parameters, vibrational characteristics, and spray particle size.

Main Methods:

• Development of a novel piezoelectric ceramic with low sintering temperature and high thermal stability (Curie temperature > 300 °C).
• Utilized COMSOL software to calculate resonance frequency and nozzle displacement.
• Applied calculated parameters to a mathematical model for ultrasonic nozzle design and fabrication.
• Experimental analysis of spray characteristics, including particle size distribution at varying nozzle lengths, frequencies, and fluid viscosities.

Main Results:

• A piezoelectric ceramic vibrator was successfully developed and integrated into an ultrasonic nozzle.
• The designed nozzle, with a horn length of 22 mm and resonance frequency of 42.1 kHz, produced average spray particle sizes of 30-40 μm at 65 mL/min flow rate.
• Mathematical analysis confirmed that increasing nozzle horn length decreases resonance frequency, reduces liquid energy supply, and increases particle size.
• Increased fluid viscosity was found to increase the energy required for atomization.

Conclusions:

• The study successfully demonstrated a mathematical model for controlling particle size in ultrasonic spray nozzles.
• The developed piezoelectric ceramic and nozzle design are suitable for industrial applications requiring fine and uniform spray particles.
• The findings provide valuable insights into optimizing ultrasonic nozzle design by correlating geometric and material properties with atomization performance.