Title:
UV Disinfection between Concentric Cylinders

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dc.contributor.advisor Forney, Larry J.
dc.contributor.author Ye, Zhengcai en_US
dc.contributor.committeeMember Agrawal, Pradeep K.
dc.contributor.committeeMember Breedveld, Victor
dc.contributor.committeeMember Pavlostathis, Spyros
dc.contributor.committeeMember Pierson, John
dc.contributor.department Chemical Engineering en_US
dc.date.accessioned 2007-05-25T17:46:48Z
dc.date.available 2007-05-25T17:46:48Z
dc.date.issued 2007-01-10 en_US
dc.description.abstract Outbreaks of food-born illness associated with the consumption of unpasteurized juice and apple cider have resulted in a rule published by the U.S. Food and Drug Administration (FDA) in order to improve the safety of juice products. The rule (21 CFR120) requires manufacturers of juice products to develop a Hazard Analysis and Critical Control Point (HACCP) plan and to achieve a 5-log reduction in the number of the most resistant pathogens. Ultraviolet (UV) disinfection is one of the promising methods to reach this 5-log reduction of pathogens. The absorption coefficients of juices typically vary from 10 to 40 1/cm and can be even higher depending on brand and processing conditions. Thin film reactors consisting of two concentric cylinders are suitable for inactivating pathogens in juices. When the two concentric cylinders are fixed, the flow pattern in the gap can be laminar Poiseuille flow or turbulent flow depending on flow rates. If the inner cylinder is rotating, and the rotating speed of the inner cylinder exceeds a certain value, the flow pattern can be either laminar or turbulent Taylor-Couette flow. UV disinfection between concentric cylinders in laminar Poiseuille flow, turbulent flow and both laminar and turbulent Taylor-Couette flow was investigated experimentally and numerically. This is the first systematic study done on UV disinfection between concentric cylinders in all three flow patterns. The present work provides new experimental data for pathogen inactivation in each of the three flow patterns. In addition, the present study constitutes the first systematic numerical CFD predictions of expected inactivation levels. Proper operating parameters and optimum gap widths for different flow patterns are suggested. It is concluded that laminar Poiseuille flow provides inferior (small) inactivation levels while laminar Taylor-Couette flow provides superior (large) inactivation levels. The relative inactivation levels are: laminar Poiseuille flow < turbulent flow < laminar Taylor-Couette flow.
dc.description.degree Ph.D. en_US
dc.identifier.uri http://hdl.handle.net/1853/14641
dc.publisher Georgia Institute of Technology en_US
dc.subject UV disinfection en_US
dc.subject Computational fluid dynamics en_US
dc.subject Numerical modeling en_US
dc.subject Taylor-Couette flow en_US
dc.subject Turbulent flow en_US
dc.subject Escherichia coli en_US
dc.subject Yersinia pseudotuberculosis en_US
dc.subject.lcsh Taylor vortices en_US
dc.subject.lcsh Ultraviolet radiation en_US
dc.subject.lcsh Disinfection and disinfectants en_US
dc.subject.lcsh Fruit juices en_US
dc.subject.lcsh Hazard Analysis and Critical Control Point (Food safety system) en_US
dc.title UV Disinfection between Concentric Cylinders en_US
dc.type Text
dc.type.genre Dissertation
dspace.entity.type Publication
local.contributor.corporatename School of Chemical and Biomolecular Engineering
local.contributor.corporatename College of Engineering
relation.isOrgUnitOfPublication 6cfa2dc6-c5bf-4f6b-99a2-57105d8f7a6f
relation.isOrgUnitOfPublication 7c022d60-21d5-497c-b552-95e489a06569
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