纵弯模式转换开缝圆管压电超声换能器

Open-slit circular tube piezoelectric ultrasonic transducer with longitudinal bending mode conversion

本文提出一种新型的纵弯模式转换开缝圆管压电超声换能器,该换能器由夹心式压电超声换能器、变幅杆和开缝圆管辐射器三部分组成.其中开缝圆管辐射器由圆管沿轴向等分切割成若干弧形片,两端为半径相等的薄圆盘端盖.本文基于Timoshenko梁理论与机电类比原理,建立了均匀弹性杆弯曲振动和超声换能器整体的机电等效电路及共振频率方程.利用等效电路法、有限元法和实验测试对换能器的振动特性进行了研究,结果表明,通过新型的结构设计和利用纵向振动夹心式压电超声换能器可有效激发开缝圆管辐射器的两端盖产生低阶纵向弯曲振动,弧形片产生高阶横向弯曲振动,从而实现高效率、均匀和全方位的超声辐射.研究成果有望在超声污水处理、超声除藻和超声化学反应等大容量液体超声处理技术中获得应用.

A new type of open-slit circular tube piezoelectric ultrasound transducer with a longitudinal bending mode conversion,comprising a sandwich piezoelectric ultrasonic transducer,an amplitude converter,and an open-slit circular tube radiator,is proposed.The open-slit circular tube radiator is cut in equal parts into several curved pieces from the circular tube along the axial direction,with thin disk end caps of equal radius at each end.The electromechanical equivalent circuits and resonant frequency equations for uniform elastic rod bending vibrations and ultrasonic transducers are derived using the Timoshenko beam theory and electromechanical analogy principle.The vibrational characteristics of the transducer are calculated using the equivalent circuit and finite element methods.The results showed that the new structural design and use of a longitudinal vibration sandwich-type piezoelectric ultrasonic transducer could effectively excite the two end caps of the open-slit circular tube radiator to produce the low-order longitudinal bending vibration and curved piece to produce the high-order transverse bending vibration,thereby achieving high efficiency,uniform,and all-round ultrasonic radiation.This research results are expected to be applied in high-volume liquid ultrasonic treatment technologies,such as ultrasonic wastewater treatment,ultrasonic algae removal,and ultrasonic chemical reactions.