Ultrasonic trapping of small particles.
Date of Issue2011
School of Electrical and Electronic Engineering
A new operating principle by using ultrasonic field near the radiation surface to trap small particles has been proposed. Based on this principle, three novel ultrasonic transducers which have relatively simple and compact structure and use ultrasonic field near the radiation surface for improving utilization energy have been proposed and researched. They are the W-shaped transducer, acoustic needle and vibrating rod. They can trap particles onto radiation surface. For each transducer, the author has proposed and investigated its structure, fabricated the prototype, investigated and measured the trapping performance. A theoretical model has been established to analyze the trapping mechanism. The guidelines for optimizing the trapping capability of each transducer have been given based on the experimental and theoretical analysis. Furthermore, a method for calculating the acoustic radiation force on a particle with arbitrary shape in an arbitrary sound field has been proposed and developed in this thesis. It can be used when the conditions of conventional methods are not satisfied.