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Some investigations on the use of ultrasonics in travelling bubble cavitation control

Chatterjee, Dhiman and Arakeri, Vijay H (2004) Some investigations on the use of ultrasonics in travelling bubble cavitation control. In: Journal of Fluid Mechanics, 504 . pp. 365-389.

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Abstract

In this paper we report results from some investigations on the use of ultrasonics in controlling travelling bubble cavitation. Control of this type of cavitation, generated using a venturi device, has been achieved by manipulation of potential nuclei using a piezoelectric device, termed the Ultrasonic Nuclei Manipulator (UNM). The performance of the UNM, activated in continuous-wave (CW) and pulsed modes, has been studied over a range of dissolved gas concentration (C). The performance under Cwexcitation is found to depend sensitively on C, with lack of control in near-saturated water samples. Failure to control cavitation at $C\approx 1$ under CW-excitation is suggested to be a result of bubble growth by recti.ed di.usion under these conditions. The pulsed mode of excitation of the UNM, in such cases, seems to be a very promising alternative. Further improvement is observed by using two piezoelectric crystals, one driven in the CW-mode and the second in pulsed mode, as the UNM. Through carefully designed experimentation, this has been traced to the movement of nuclei under the in.uence of Bjerknes forces. Besides reduction of noise, other measures of control have been identi.ed and investigated. For example, it has been found that the maximum velocity achievable at the venturi throat can be increased from about $15ms^{-1}$ to about $22ms^{-1}$ with nuclei manipulation using ultrasonics.

Item Type: Journal Article
Additional Information: The copyright belongs to Cambridge University Press.
Department/Centre: Division of Mechanical Sciences > Mechanical Engineering
Date Deposited: 26 Apr 2006
Last Modified: 19 Sep 2010 04:25
URI: http://eprints.iisc.ernet.in/id/eprint/6475

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