Design of a high intensity ultrasound dispersion cell

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dc.contributor.advisorTapson, Jonathanen_ZA
dc.contributor.advisorMortimer, Bruceen_ZA
dc.contributor.authorFoster, Clintonen_ZA
dc.date.accessioned2015-09-15T10:02:43Z
dc.date.available2015-09-15T10:02:43Z
dc.date.issued2003en_ZA
dc.descriptionIncludes bibliographical references.en_ZA
dc.description.abstractThe aim of this project was to provide detailed research on the factors causing mechanical damage in a high power ultrasound environment, and to give recommendations for the production of an ultrasonic dispersion cell with a removable treatment vessel. The primary mechanism for causing this dispersion was cavitation: a void of air or vapour in a liquid medium that grows and collapses in an intense ultrasonic sound field. The secondary mechanism was a phenomenon called acoustic streaming which provides a macro mixing effect, also caused by intense ultrasound. Streaming and, even more so, cavitation were difficult to measure and for this reason a refinement of a method to map cavitation fields with aluminium foil was developed. This involved using digital image processing to extract quantitative information from damaged foil samples. A large portion of the project focused on the overcoming of absorption and subsequent rapid attenuation of sound between the transducer (ultrasonic source) and the treatment vessel. This absorption was due to a number of interrelated factors: reflection of sound at material boundaries; cavitation clouds causing sound scattering; energy absorption; and conventional absorption in liquids due to viscous damping. A number of strategies were employed to overcome this absorption problem: the use of increased static pressure to suppress cavitation in certain areas; the use of multiple transducers; and, as a result, multiple paths for the sound to enter the vessel. A combination of static pressure and multiple transducers were also tested. A number of different media were tested for their ability to transmit sound and an optimum solution was recommended. Streaming and the physical constraints affecting streaming in the treatment vessel were tested to give a practical guide to the factors producing streaming. Then, as the temperature of the liquid affects absorption, cavitation threshold, and the ability of a solvent to dissolve, a look at the thermal aspects of the system was discussed.en_ZA
dc.identifier.apacitationFoster, C. (2003). <i>Design of a high intensity ultrasound dispersion cell</i>. (Thesis). University of Cape Town ,Faculty of Engineering & the Built Environment ,Department of Electrical Engineering. Retrieved from http://hdl.handle.net/11427/13916en_ZA
dc.identifier.chicagocitationFoster, Clinton. <i>"Design of a high intensity ultrasound dispersion cell."</i> Thesis., University of Cape Town ,Faculty of Engineering & the Built Environment ,Department of Electrical Engineering, 2003. http://hdl.handle.net/11427/13916en_ZA
dc.identifier.citationFoster, C. 2003. Design of a high intensity ultrasound dispersion cell. University of Cape Town.en_ZA
dc.identifier.ris TY - Thesis / Dissertation AU - Foster, Clinton AB - The aim of this project was to provide detailed research on the factors causing mechanical damage in a high power ultrasound environment, and to give recommendations for the production of an ultrasonic dispersion cell with a removable treatment vessel. The primary mechanism for causing this dispersion was cavitation: a void of air or vapour in a liquid medium that grows and collapses in an intense ultrasonic sound field. The secondary mechanism was a phenomenon called acoustic streaming which provides a macro mixing effect, also caused by intense ultrasound. Streaming and, even more so, cavitation were difficult to measure and for this reason a refinement of a method to map cavitation fields with aluminium foil was developed. This involved using digital image processing to extract quantitative information from damaged foil samples. A large portion of the project focused on the overcoming of absorption and subsequent rapid attenuation of sound between the transducer (ultrasonic source) and the treatment vessel. This absorption was due to a number of interrelated factors: reflection of sound at material boundaries; cavitation clouds causing sound scattering; energy absorption; and conventional absorption in liquids due to viscous damping. A number of strategies were employed to overcome this absorption problem: the use of increased static pressure to suppress cavitation in certain areas; the use of multiple transducers; and, as a result, multiple paths for the sound to enter the vessel. A combination of static pressure and multiple transducers were also tested. A number of different media were tested for their ability to transmit sound and an optimum solution was recommended. Streaming and the physical constraints affecting streaming in the treatment vessel were tested to give a practical guide to the factors producing streaming. Then, as the temperature of the liquid affects absorption, cavitation threshold, and the ability of a solvent to dissolve, a look at the thermal aspects of the system was discussed. DA - 2003 DB - OpenUCT DP - University of Cape Town LK - https://open.uct.ac.za PB - University of Cape Town PY - 2003 T1 - Design of a high intensity ultrasound dispersion cell TI - Design of a high intensity ultrasound dispersion cell UR - http://hdl.handle.net/11427/13916 ER - en_ZA
dc.identifier.urihttp://hdl.handle.net/11427/13916
dc.identifier.vancouvercitationFoster C. Design of a high intensity ultrasound dispersion cell. [Thesis]. University of Cape Town ,Faculty of Engineering & the Built Environment ,Department of Electrical Engineering, 2003 [cited yyyy month dd]. Available from: http://hdl.handle.net/11427/13916en_ZA
dc.language.isoengen_ZA
dc.publisher.departmentDepartment of Electrical Engineeringen_ZA
dc.publisher.facultyFaculty of Engineering and the Built Environment
dc.publisher.institutionUniversity of Cape Town
dc.subject.otherElectrical Engineeringen_ZA
dc.titleDesign of a high intensity ultrasound dispersion cellen_ZA
dc.typeMaster Thesis
dc.type.qualificationlevelMasters
dc.type.qualificationnameMScen_ZA
uct.type.filetypeText
uct.type.filetypeImage
uct.type.publicationResearchen_ZA
uct.type.resourceThesisen_ZA
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