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Numerical and experimental studies on the effect of surface roughness and ultrasonic frequency on bubble dynamics in acoustic cavitation

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Altay, Rana and Sadaghiani, Abdolali Khalili and Sevgen, İlker and Şişman, Alper and Koşar, Ali (2020) Numerical and experimental studies on the effect of surface roughness and ultrasonic frequency on bubble dynamics in acoustic cavitation. Energies, 13 (5). ISSN 1996-1073

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Official URL: http://dx.doi.org/10.3390/en13051126

Abstract

With many emerging applications such as chemical reactions and ultrasound therapy, acoustic cavitation plays a vital role in having improved energy efficiency. For example, acoustic cavitation results in substantial enhancement in the rates of various chemical reactions. In this regard, an applied acoustic field within a medium generates acoustic streaming, where cavitation bubbles appear due to preexisting dissolved gas in the working fluid. Upon cavitation inception, bubbles can undergo subsequent growth and collapse. During the last decade, the studies on the effects of different parameters on acoustic cavitation such as applied ultrasound frequency and power have been conducted. The bubble growth and collapse mechanisms and their distribution within the medium have been classified. Yet, more research is necessary to understand the complex mechanism of multi-bubble behavior under an applied acoustic field. Various parameters affecting acoustic cavitation such as surface roughness of the acoustic generator should be investigated in more detail in this regard. In this study, single bubble lifetime, bubble size and multi-bubble dynamics were investigated by changing the applied ultrasonic field. The effect of surface roughness on bubble dynamics was presented. In the analysis, images from a high-speed camera and fast video recording techniques were used. Numerical simulations were also done to investigate the effect of acoustic field frequency on bubble dynamics. Bubble cluster behavior and required minimum bubble size to be affected by the acoustic field were obtained. Numerical results suggested that bubbles with sizes of 50 mu m or more could be aligned according to the radiation potential map, whereas bubbles with sizes smaller than 10 mu m were not affected by the acoustic field. Furthermore, it was empirically proven that surface roughness has a significant effect on acoustic cavitation phenomena.

Item Type:Article
Additional Information:Wos Document Type: Article; Proceedings Paper (Conference: 16th UK Heat Transfer Conference (UKHTC) / Location: Univ Nottingham, Nottingham, ENGLAND / Date: SEP 08-10, 2019)
Uncontrolled Keywords:acoustic cavitation; surface roughness; cavitation bubble; bubble dynamics; bubble size; bubble growth
Subjects:T Technology > T Technology (General)
T Technology > TJ Mechanical engineering and machinery
ID Code:40047
Deposited By:Ali Koşar
Deposited On:27 Aug 2020 14:33
Last Modified:27 Aug 2020 14:33

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