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

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.