• Mackersie, John
• Wang, Chuangnan
• Oleary, Richard
• Gachagan, Anthony

Abstract

High power ultrasound can be used as a catalysis to <br/>enhance the efficiency of chemical reactions. The generation of <br/>cavitation accelerates the reaction. The ultrasonic system in <br/>sonochemistry is typically based on single-frequency transducers, <br/>with some reactor designs incorporating multiple transducers <br/>operating at different frequencies. Currently, high intensity <br/>focused ultrasound (HIFU) is mainly used in clinical applications, <br/>such as prostate cancer surgery - high frequency ultrasound is <br/>utilized to provide accurate focusing and prevent cavitation. This <br/>paper considers the application of the HIFU technique in <br/>sonochemistry, in which an array transducer is used to generate <br/>cavitation through its steering ability. In this paper, the HIFU <br/>array transducer is based on a stacked, 2-2 connectivity <br/>piezoelectric composite and is configured as a 1-D linear array. As <br/>the goal is to produce cavitation in a liquid load, the operating <br/>frequency is below 500kHz. A 2-layer stacked structure, without <br/>backing, is adopted to increase the thickness of composite and <br/>reduce frequency. Due to the high acoustic impedance of the <br/>piezoceramic composite, a two matching layer system is applied to <br/>improve the coupling efficiency. The prototype array has been <br/>calibrated through experimental measurements of acoustic <br/>pressure field, impulse response and cavitating field. <br/>

Topics

• impedance spectroscopy
• composite
• ultrasonic