Characterisation of mixing rate due to high power ultrasound

Yusaf, Talal and Buttsworth, David R. (2007) Characterisation of mixing rate due to high power ultrasound. Ultrasonics Sonochemistry, 14 (2). pp. 266-274. ISSN 1350-4177

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Abstract

For meaningful assessment of results from laboratory and pilot plant trials, it is often necessary to know the mixing characteristics within the ultrasonic reactors. Previous workers have used conductivity measurements in an attempt to characterize the residence time distribution in ultrasonic reactors, but these results do not provide direct data on the mixing within the high power region adjacent to the ultrasonic probe tip. We overcome this difficulty though direct visualization of the mixing process within the high energy region close to the tip of the ultrasonic probe. Our analysis proceeds by determining an approximate turbulent diffusivity in a batch reactor arrangement for different values of ultrasonic energy input. For input electrical power levels between 70 and 120 W and a processing volume of 30 ml, the effective turbulent diffusivity varied from about 0.2e-3 m^2/s to 0.7e-3 m^2/s. We demonstrate that such results can be coupled to a suitable dispersion model to estimate the actual residence time distribution in flow-though arrangements when the through-put adds little additional mixing energy. Therefore, coupling the effective turbulent diffusivity identified in a batch reactor with a suitable dispersion model for the reactor therefore offers an alternative approach to the deduction of RTD when determining the actual RTD in the high intensity zone of steady flow sonochemical reactors is problematic.


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Item Type: Article (Commonwealth Reporting Category C)
Refereed: Yes
Item Status: Live Archive
Additional Information: Deposited in accordance with the copyright policy of the publisher.
Depositing User: Assoc Prof David Buttsworth
Faculty / Department / School: Historic - Faculty of Engineering and Surveying - Department of Mechanical and Mechatronic Engineering
Date Deposited: 11 Oct 2007 00:50
Last Modified: 02 Jul 2013 22:39
Uncontrolled Keywords: ultrasonic processing; turbulent mixing; turbulent diffusivity; mixing time; residence time distribution
Fields of Research (FOR2008): 09 Engineering > 0915 Interdisciplinary Engineering > 091508 Turbulent Flows
09 Engineering > 0906 Electrical and Electronic Engineering > 090607 Power and Energy Systems Engineering (excl. Renewable Power)
09 Engineering > 0904 Chemical Engineering > 090407 Process Control and Simulation
Socio-Economic Objective (SEO2008): E Expanding Knowledge > 97 Expanding Knowledge > 970109 Expanding Knowledge in Engineering
Identification Number or DOI: doi: 10.1016/j.ultsonch.2006.04.008
URI: http://eprints.usq.edu.au/id/eprint/1729

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