Investigation of Ultrasonic Sonotrode Design to Improve the Performance of Ultrasonic Fouling Removal

Fouling build-up is a well-known industrial problem and its accumulation is dependent on the conditions surrounding the structure. Conventional fouling removal methods are costly and also require an operational halt to carry out the procedure. The use of Ultrasonics has gained popularity in recent years as a non-invasive means of fouling removal but further research and development are required to improve and optimize the technology. Currently in industry, Ultrasonic horns are designed and optimized to generate high amplitude vibrations for various applications including welding, cutting and sonochemistry. Some research has been done to design horns for the generation of cavitation, but none specifically for fouling removal applications. This work investigates the addition of half-wavelength transducer horns of varying shapes (cylindrical, conical, exponential and stepped) to an existing 40 kHz cleaning transducer. Numerical modelling is carried out to optimize the length of the horn before manufacturing final geometries. Experiments were conducted to attach an ultrasonic horn to the transducer and to a carbon steel plate (300 mm × 300 mm × 2 mm), and to measure wave propagation across the structure using a PSV-400 3D Laser Scanning Vibrometer. This has shown that the addition of an ultrasonic horn improves the out-of-plane displacement across the structure, which correlates to an improvement in fouling removal for steel tube ultrasonic cleaning.