Title:
Dynamics of swirling flows induced by twisted tapes in circular pipes

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dc.contributor.advisor Aidun, Cyrus K.
dc.contributor.author Cazan, Radu en_US
dc.contributor.committeeMember Ghiaasiaan, S. Mostafa
dc.contributor.committeeMember Glezer Ari
dc.contributor.committeeMember Seitzman Jerry
dc.contributor.committeeMember Webster Donald
dc.contributor.committeeMember Yoda Minami
dc.contributor.department Mechanical Engineering en_US
dc.date.accessioned 2010-06-10T16:59:29Z
dc.date.available 2010-06-10T16:59:29Z
dc.date.issued 2010-04-02 en_US
dc.description.abstract The present study describes the flow characteristics of swirling flows induced by twisted tape inserts in circular pipes. The study is focused on the secondary flow which is investigated experimentally and with numerical models. The results are expected to improve the paper manufacturing process by identifying and removing the detrimental secondary flow. Experimental tests show for the first time the existence of two co-rotating helical vortices superimposed over the main swirling flow, downstream of twisted tapes. The close proximity of the two co-rotating vortices creates a local counter-rotating flow at the pipe centerline. The flow is analyzed using LDV measurements and high speed camera visualization with fine air bubbles seeding which confirm that the helical vortices are stable. After extracting the characteristic tangential velocity profiles of the main vortex and of the two secondary vortices, it was observed that the maximum tangential velocity of all three vortices is the same, approximately half of the bulk velocity. The winding of the helical vortices is in the swirl direction and the pitch of the helical vortices is found to be independent of the inlet velocity. The experimental findings are confirmed by numerical simulations. The numerical results show that the helical vortices originate inside the swirler and evolve from single co-rotating vortices on each side of the tape. The flow characteristics are analyzed in detail. Swirlers with multiple twists and multiple chambers are shown to have less stable secondary motion and could be employed in applications were the secondary motion is detrimental. en_US
dc.description.degree Ph.D. en_US
dc.identifier.uri http://hdl.handle.net/1853/33944
dc.publisher Georgia Institute of Technology en_US
dc.subject Helical vortex en_US
dc.subject Swirling flow en_US
dc.subject Flow visualization en_US
dc.subject Twisted tape en_US
dc.subject Vortex dynamics en_US
dc.subject Rotating fluids en_US
dc.subject.lcsh Eddies
dc.subject.lcsh Turbulence
dc.subject.lcsh Pipe Fluid dynamics
dc.subject.lcsh Vortex-motion
dc.title Dynamics of swirling flows induced by twisted tapes in circular pipes en_US
dc.type Text
dc.type.genre Dissertation
dspace.entity.type Publication
local.contributor.advisor Aidun, Cyrus K.
local.contributor.corporatename George W. Woodruff School of Mechanical Engineering
local.contributor.corporatename College of Engineering
relation.isAdvisorOfPublication 4b7dc133-2272-48c8-90bc-5f8401a4222c
relation.isOrgUnitOfPublication c01ff908-c25f-439b-bf10-a074ed886bb7
relation.isOrgUnitOfPublication 7c022d60-21d5-497c-b552-95e489a06569
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