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dc.contributor.authorrodriguez, salvador
dc.date.accessioned2011-07-02T17:38:44Z
dc.date.available2011-07-02T17:38:44Z
dc.date.issued2011-07-02
dc.date.submittedMay 2011
dc.identifier.urihttp://hdl.handle.net/1928/12873
dc.description.abstractThe literature indicates that a prismatic-core very high temperature reactor can experience thermal stratification and hot spot issues in the lower plenum (LP). This research hypothesizes that the complex thermalhydraulic phenomena in the LP requires a sophisticated computational fluid dynamics (CFD) code with state-of-the-art turbulence models and advanced swirling jet technology to mitigate the two issues. The primary research goals were to increase the heat transfer and mixing capacity of swirling jets, extend swirling jet theory, and to apply those advancements for the mitigation of the thermalhydraulic issues. First, it was demonstrated that the Fuego CFD code successfully modeled a set of key LP thermalhydraulic phenomena. Thereafter, a helicoid vortex swirl model was developed to investigate the impact of the swirl number (S) on mixing and heat transfer. The development of azimuthal and axial velocities that are purely functions of S permitted the analysis of the central recirculation zone’s (CRZ) impact on the LP flow field. At this point, several characteristics were found in common between the helicoid vortex and other axisymmetric, Newtonian, incompressible vortices found in the literature. This observation resulted in a more fundamental understanding of how vortices behave, and which traits can be exploited for the purpose of maximizing heat transfer and mixing. Because the CRZ is a strong function of the azimuthal and axial velocities, shaping those velocity profiles had a substantial impact on the flow field. Eventually, this led to the discovery that vortices may be expressed as alternating series that expand geometrically with odd exponents. This helped corroborate that the 15 axisymmetric vortices discussed in this research are part of a vortex family with seven common traits. This also led to the development of new vortices that are based on one or two series terms that satisfy the Navier-Stokes equations and conservation of mass. In addition, the impact of Reynolds number and swirl decay were explored in order to further quantify their impact on mixing and heat transfer. Finally, the above theories and modeling insights were applied towards a comprehensive set of LP calculations that showed that the swirling jets mitigated the entrainment and hot spot issues, while resulting in a reasonable pressure drop.en_US
dc.description.sponsorshipsandia national laboratoriesen_US
dc.language.isoen_USen_US
dc.subjectswirling jet vortex turbulence mixing vhtr nuclear lower plenum cfd crzen_US
dc.subjecthelicoiden_US
dc.subject.lcshNuclear reactors ǂx Fluid dynamics.
dc.subject.lcshPlasma turbulence.
dc.subject.lcshJets--Fluid dynamics.
dc.subject.lcshSuperheating reactors.
dc.titleSwirling jets for the mitigation of hot spots and thermal Sstratification in the VHTR lower plenumen_US
dc.typeDissertationen_US
dc.description.degreenuclear engineeringen_US
dc.description.levelDoctoralen_US
dc.description.departmentUniversity of New Mexico. Dept. of Chemical and Nuclear Engineeringen_US
dc.description.advisorel-genk, mohamed
dc.description.committee-memberpetsev, dimiter
dc.description.committee-membersteinberg, stanly
dc.description.committee-memberde oliveira, cassiano
dc.description.committee-memberhassan, basil


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