Show simple item record

AuthorWeber, Markusdc.contributor.author
Date of accession2016-03-14T11:54:16Zdc.date.accessioned
Available in OPARU since2016-03-14T11:54:16Zdc.date.available
Year of creation2002dc.date.created
AbstractStationary thermal convection was investigated in two-dimensional 100 x 50 site percolation models with the aid of numerical simulations based on the finite volume method (FVM). For the Rayleigh-Bénard configuration in the non-disturbed pore space a critical Rayleigh number exists below which only heat from incoherent motion can be transported. A local investigation of porous systems shows that with different heat conductivities between the matrix and the liquid coherent motion exists even below the critical Rayleigh number. These numerical investigations have been extended to real systems. Thus, with NMR velocity imaging stationary thermal convection on quasi two-dimensional site percolation models could be investigated. Direct comparison with numerical simulation led to good agreement not only for flow pathways but also for the velocity distribution functions. Apart from velocity maps temperature maps could help to characterize thermal convection. The spatial temperature distribution of thermal convection in a two-dimensional site percolation model has been measured. The temperature map compares well with the corresponding velocity map. Besides the hydrodynamic flow and the diffusion in porous media the investigation of transport of electric particles in percolation clusters is of major interest in percolation theory. With the aid of NMR current density imaging the spatial distribution of flow paths of electric currents in 60 x 60 two-dimensional site percolation model objects could be visualized for the first time. With this the experimental results could directly be compared to numerical simulations which are based on potential theory. The experiments and their corresponding simulations show a very good agreement in the current density maps as well as in the current density distribution functions. For comparing between electrical current and hydrodynamic transport, pressure-driven flow in the same porous structures was examined by using NMR velocity imaging.dc.description.abstract
Languagededc.language.iso
PublisherUniversität Ulmdc.publisher
LicenseStandard (Fassung vom 03.05.2003)dc.rights
Link to license texthttps://oparu.uni-ulm.de/xmlui/license_v1dc.rights.uri
KeywordFVMdc.subject
KeywordGeschwindigkeitsbildgebungdc.subject
KeywordGitterplatzdc.subject
LCSHFinite volume methoddc.subject.lcsh
LCSHHeat convection: Computer simulationdc.subject.lcsh
LCSHNuclear magnetic resonancedc.subject.lcsh
LCSHPercolation: Statistical physicsdc.subject.lcsh
LCSHPorous materialsdc.subject.lcsh
LCSHTransport theorydc.subject.lcsh
TitleTransportprozesse in Gitterplatzmodellen: Simulation und NMR-Experimentedc.title
Resource typeDissertationdc.type
DOIhttp://dx.doi.org/10.18725/OPARU-77dc.identifier.doi
URNhttp://nbn-resolving.de/urn:nbn:de:bsz:289-vts-18229dc.identifier.urn
GNDKonvektiondc.subject.gnd
GNDMagnetische Kernresonanzdc.subject.gnd
GNDPerkolationdc.subject.gnd
GNDPoröser Stoffdc.subject.gnd
GNDWärmestromdichtedc.subject.gnd
FacultyFakultät für Naturwissenschaftenuulm.affiliationGeneral
Date of activation2002-07-20T11:57:48Zuulm.freischaltungVTS
Peer reviewneinuulm.peerReview
Shelfmark print versionZ: J-H 7.815 ; W: W-H 7.215ZAV: J-H 5.350uulm.shelfmark
DCMI TypeTextuulm.typeDCMI
VTS-ID1822uulm.vtsID
CategoryPublikationenuulm.category


Files in this item

Thumbnail

This item appears in the following Collection(s)

Show simple item record