Design of high-intensity ultrasound reactor

Johansson, Örjan; Löfqvist, Torbjörn; Pamidi, Taraka Rama Krishna

doi:10.1109/ultsym.2017.8092948

Cited by 1 publication

(2 citation statements)

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“…Designing a matching layer sandwiched between media based on the long-established impedance-translation theorem is sensible and valid in simple cases of wave propagation or acoustic analog of a transmission line [1,2]. However, such an approach is also practiced to optimize sound emission from a piezoelectric transducer [3][4][5][6][7][8][9][10][11][12][13][14][15][16][17] albeit in a way that neglects the piezoelectric and elastic aspects of the layers. Moreover, the intention is to maximize the acoustic emission from the system and not just eliminate reflections at the interface between the matching layer and the transducer.…”

Section: Debunking a Common Misconceptionmentioning

confidence: 99%

“…Moreover, small amounts of hydrogen can be produced in the presence of intensive ultrasound [12]. At intensities significantly above the cavitation threshold, such as a standing ultrasonic wave in a cavity, extreme erosion of aluminum can be achieved within seconds [13]. Sufficiently dense inertial cavitation causes rapid removal of the oxide layer and then exposes aluminum to a rapid reaction with water that releases hydrogen [14].…”

Section: Introductionmentioning

confidence: 99%

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Titanium ultrasonic reactor tuned to 500 kHz

Seifer

2023

Acta Acust.

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This study describes the design considerations, principles, and performance of a water-filled ultrasonic reactor formed by a 125 mm size titanium cylinder covered with 67 piezoelectric transducers, tuned as a system for peak emissions at 500 kHz. The total acoustic power measured by a radiation force balance is 107 W. The sound intensity is amplified by the cavity and focusing attributes of the cylindrical wall. The reactor can generate ZnO nanoparticles from ZnAc2 solution, and the nanoparticle are found fixated to an epoxy substrate as observed under a scanning transmission electron microscope. These indications are similar to a sonochemical reaction reported at 20 kHz, which validates that inertial cavitation has been reached. The titanium wall has a transmission efficiency of 51% compared to a well-matched POCO graphite-resin layer. The efficiency exceeds the value of 17% expected from a naïve calculation based on the impedance-translation theorem. The problem of optimal emission from a piezoelectric source is more complex than a simple reduction of reflections at the transducer boundary. COMSOL simulations show that the condition for optimal transmission requires consideration of elasticity and piezoelectric charge matrices instead of acoustic impedance. Approximated analytical calculation is suggested as a preliminary guidance for design of an optimal matching layer.

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