TY - JOUR

T1 - Closed loop cavitation control - A step towards sonomechatronics

AU - Saalbach, Kai Alexander

AU - Ohrdes, Hendrik

AU - Twiefel, Jens

PY - 2018/6

Y1 - 2018/6

N2 - In the field of sonochemistry, many processes are made possible by the generation of cavitation. This article is about closed loop control of ultrasound assisted processes with the aim of controlling the intensity of cavitation-based sonochemical processes. This is the basis for a new research field which the authors call “sonomechatronics”. In order to apply closed loop control, a so called self-sensing technique is applied, which uses the ultrasound transducer's electrical signals to gain information about cavitation activity. Experiments are conducted to find out if this self-sensing technique is capable of determining the state and intensity of acoustic cavitation. A distinct frequency component in the transducer's current signal is found to be a good indicator for the onset and termination of transient cavitation. Measurements show that, depending on the boundary conditions, the onset and termination of transient cavitation occur at different thresholds, with the onset occurring at a higher value in most cases. This known hysteresis effect offers the additional possibility of achieving an energetic optimization by controlling cavitation generation. Using the cavitation indicator for the implementation of a double set point closed loop control, the mean driving current was reduced by approximately 15% compared to the value needed to exceed the transient cavitation threshold. The results presented show a great potential for the field of sonomechatronics. Nevertheless, further investigations are necessary in order to design application-specific sonomechatronic processes.

AB - In the field of sonochemistry, many processes are made possible by the generation of cavitation. This article is about closed loop control of ultrasound assisted processes with the aim of controlling the intensity of cavitation-based sonochemical processes. This is the basis for a new research field which the authors call “sonomechatronics”. In order to apply closed loop control, a so called self-sensing technique is applied, which uses the ultrasound transducer's electrical signals to gain information about cavitation activity. Experiments are conducted to find out if this self-sensing technique is capable of determining the state and intensity of acoustic cavitation. A distinct frequency component in the transducer's current signal is found to be a good indicator for the onset and termination of transient cavitation. Measurements show that, depending on the boundary conditions, the onset and termination of transient cavitation occur at different thresholds, with the onset occurring at a higher value in most cases. This known hysteresis effect offers the additional possibility of achieving an energetic optimization by controlling cavitation generation. Using the cavitation indicator for the implementation of a double set point closed loop control, the mean driving current was reduced by approximately 15% compared to the value needed to exceed the transient cavitation threshold. The results presented show a great potential for the field of sonomechatronics. Nevertheless, further investigations are necessary in order to design application-specific sonomechatronic processes.

KW - Cavitation

KW - Closed loop cavitation control

KW - Closed loop control

KW - Sonochemistry

UR - http://www.scopus.com/inward/record.url?scp=85041518224&partnerID=8YFLogxK

U2 - 10.1016/j.ultsonch.2018.01.021

DO - 10.1016/j.ultsonch.2018.01.021

M3 - Article

C2 - 29680596

AN - SCOPUS:85041518224

VL - 44

SP - 14

EP - 23

JO - Ultrasonics Sonochemistry

JF - Ultrasonics Sonochemistry

SN - 1350-4177

ER -