# A Dual Frequency Ultrasonic Cleaning Tank Developed by Transient Dynamic Analysis
###### Abstract  
At present, development of manufacturer's ultrasonic cleaning tank (UCT) to match the requirements from consumers usually relies on computer simulation based on harmonic response analysis (HRA). However, this technique can only be used with single-frequency UCT. For dual frequency, the manufacturer used information from empirical experiment alongside trial-and-error methods to develop prototypes, resulting in the UCT that may not be fully efficient. Thus, lack of such a proper calculational method to develop the dual frequency UCT was a problem that greatly impacted the manufacturers and consumers. To resolve this problem, we proposed a new model of simulation using transient dynamics analysis (TDA) which was successfully applied to develop the prototype of dual frequency UCT, 400 W, 18 L in capacity, eight horn transducers, 28 and 40 kHz frequencies for manufacturing. The TDA can indicate the acoustic pressure at all positions inside the UCT in transient states from the start to the states ready for proper cleaning. The calculation also reveals the correlation between the positions of acoustic pressure and the placement positions of transducers and frequencies. In comparison with the HRA at 28 kHz UCT, this TDA yielded the results more accurately than the HRA simulation, comparing to the experiments. Furthermore, the TDA can also be applied to the multifrequency UCTs as well. In this article, the step-by-step development of methodology was reported. Finally, this simulation can lead to the successful design of the high-performance dual frequencies UCT for the manufacturers. acoustic pressure; cavitation; harmonic response analysis; piezoelectric transducer; simulation; transient dynamic analysis; ultrasonic cleaning +
Footnote †: journal:  
and stable cavitation within the tank inevitably occurred [14]. This caused objects to be inefficiently cleaned. From previous research, we discovered that the dual frequency UCT helped reduce standing waves and stable cavitation. This caused better transient cavitation and thus generated various sizes of bubbles, accelerating the bubbles' collapsing rates, and intensifying the acoustic pressure within the bubbles [15; 16; 17; 18; 19; 20; 21; 22] which benefited the cleaning process of small and complex shaped objects. Therefore, advanced factories that require these objects to be exceptionally clean widely used dual or multifrequency UCTs [14; 1; 1; 13; 15; 16; 17; 18; 19; 20; 21; 22]. In the past, the development of computer simulations based on finite element method (FEM) was used to improve sonoreactors [23; 24; 25], ultrasonic transducers [26], and UCT [27] to help create the cavitation effect to the highest level [27]. Furthermore, our recent work cooperating with a manufacturer to develop a 28 kHz UCT showed that using the harmonic response analysis (HRA) in FEM can be credible, and suitable to be applied and actually used commercially [28; 29; 30; 31]. However, HRA could only be used for the single frequency UCT and was not enough for the further recent demand. Therefore, the challenge for this research was finding a method to develop a dual frequency UCT that could yield accurate results and could be practically used in the industries. From further research, it was indicated that transient dynamic analysis (TDA) was used to design multifrequency ultrasonic transducers [26], investigate the vibration that occurs in the ultrasonic dental scaler tip [10], and improve the piezoelectric micropump for fuel delivery system [32]. As the TDA were used to investigate the vibrations that occur from various conditions that differed in terms of time, it exhibits potential to be applied in the dual frequency UCT. Since the TDA has never been used in development of the UCT or calculation of the acoustic pressure before, the challenge of this research was that the authors must determine how to apply the TDA into the actual cleaning conditions in the industry.