Systematic investigation of the ultrasonic cup-type radiator based on acoustic black hole for efficient focalization and cavitation.

In many technologies such as sonochemical processing, ultrasonic-assisted advanced oxidation, and precision medicine, how to optimize conventional ultrasonic radiators to achieve efficient energy focusing and precise cavitation enhancement has become a core technical bottleneck. Hence, this paper proposes a novel cup-type ultrasonic radiator design that synergistically integrates dual acoustic black hole (ABH) profiles with a mode-conversion vibration architecture to achieve enhanced energy focalization and cavitation. Electromechanical equivalent circuit models are established for the ABH cup-type radiator (ABHCR), and its vibration performance and acoustic field characteristics are systematically investigated using both the finite element method (FEM) and experiments. The results demonstrate that the synergy between the dual-ABH profiles disk and the metal tube forms a high-intensity superimposed acoustic field inside the radiator. Compared with a conventional cup-type radiator (CCR), the dual-ABH design significantly increases the on-axis sound pressure in both air and water. Furthermore, ultrasonic emulsification experiments combined with conductivity measurements are conducted to verify and quantify the enhancement in sonochemical performance, confirming the effectiveness of the upgraded model. By enabling efficient, spatially localized focalization and cavitation, the ABHCR offers a promising platform for air-coupled ultrasonic applications, ultrasound-assisted nanomaterial synthesis, advanced oxidation processes, and scalable cavitation-assisted reactor engineering.