Different from the general ultrasonic atomizer
\noperating at high frequency, the proposed one is driven at much lower
\nfrequency but with larger amplitude. For this application purpose, a
\nsimple structure constructed with a hollow tube encircled with
\npiezoelectric actuators is considered to use. Instead of using a
\nring type of ceramics, three pieces of same size sectional-type of
\nd33 ceramic actuators are employed around the hollow tube with
\nequal distance to generate higher radial vibration. While the tube
\nfixed at both ends is vibrated with assigned vibration mode shape, a
\nsuitable wave is formed to produce larger amplitude in need. The fluid
\ninside the tube will flow out smoothly from a very small hole
\nimplemented on the largest amplitude of the waveform. Thereafter,
\natomization occurs on the tube surface around the hole immediately
\nwhile enough oscillation frequency and amplitude is provided. With
\nsuch design structure, several cases with different tube length,
\nresonance frequency, vibration amplitude are investigated for
\ncomparison. Particle size of 5~30\u03bcm and uniform spray distribution is
\nthe target for an example of industry-used spray fluid with viscosity of
\nabout 8~12cp. A measurement system is set up including high speed
\ncamera, laser as a light source, and software Image J for estimation of
\nparticle size and particle distribution. Water is used for experimental
\ntesting in this study. While drives the hollow tube with operating
\nfrequency of 45.3 kHz and the maximum amplitude is great than
\n6.8\u03bcm, atomization occurs with average particle diameter of 28.3\u03bcm
\nand good uniformity and distribution. However, increasing vibration
\namplitude, on the contrary, the diameter of the particle becomes larger.
\nFor example, while increases amplitude up to 9\u03bcm, atomization occurs
\nwith average particle diameter of 34\u03bcm, and the uniformity and
\ndistribution becomes worse. This interesting phenomenon may result
\nfrom large amplitude at enough vibration frequency easily makes
\natomization occur but large amplitude engenders with large particle
\ndiameter.<\/p>","protected":false},"author":29,"featured_media":0,"template":"","class_list":["post-3620","faculty-post","type-faculty-post","status-publish","hentry"],"acf":[],"yoast_head":"\n