Study on the vibration performance and sound field of a novel push-pull ultrasonic transducer with slotted tube.

To address the challenges in ultrasonic processing for large capacity liquids, improving the electroacoustic conversion efficiency, expanding the radiation direction, and enhancing the uniformity of the sound field have become imperative and focal objectives in the design of high-power ultrasonic transducers. Hence, a novel push-pull slotted tube ultrasonic transducer (PSTUT) based on longitudinal-bending mode conversion has been proposed. The PSTUT is composed of four key parts: two sandwich transducers, two stepped horns, two end caps, and a slotted tube radiator. By applying push-pull longitudinal excitation, the caps produce longitudinal bending vibration, while the arc-shaped plates produce radial bending vibration, capable of achieving efficient, uniform, and omnidirectional ultrasound radiation. Based on the principle of electromechanical analogy and the theory of Timoshenko beams, the electromechanical equivalent circuits of the uniform beam in bending vibration and the PSTUT in coupled vibration are established. The frequency response of the PSTUT is validated by the finite element method simulations and experiments. The vibration analysis demonstrates that adjusting the size of the circular slotted tube radiator can control both the range and intensity of radial radiation. Simulated and experimental results show that the PSTUT exhibits satisfactory 3D-omnidirectional radiation capability and improved sound field uniformity in water. The proposed PSTUT offers a promising solution to overcome the bottleneck in ultrasonic liquid treatment technology.