Atomization of high‐viscosity materials by one‐point convergence of sound waves radiated from an aerial ultrasonic source using a square transverse vibrating plate

Abstract

It is difficult to atomize high‐viscosity materials such as oil without contact; however, it is possible to do so using intense aerial ultrasonic waves. As a sound source for that purpose, an aerial ultrasonic source with 20‐kHz resonance frequency was used along with a square transverse vibrating plate that has the nodal mode of vibration amplitude in the shape of a lattice. The source radiates four‐directional sound waves in the far field. To obtain high sound pressure in the near field, radiated sound waves were converged using several flat boards and four parabolic reflective boards placed near the source. Sound pressure reaches 6.5 kPa (S.P.L. 170 dB), a very high level, at the convergent point. Scattering and atomization of the high‐viscosity materials were examined at the point of convergence. Results show the following. Atomization by a sound wave is possible in the case of high‐viscosity materials. The higher the sound pressure, the shorter the beginning time of atomization becomes. The distribution of the atomized particles diameter is 0.05–0.22 mm at the movement viscosity of 10<th>000 cSt.