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dc.contributor.advisorMesarovic, Sinisa Dj.
dc.creatorDEHSARA, MOHAMMAD
dc.date.accessioned2018-05-08T16:54:19Z
dc.date.available2018-05-08T16:54:19Z
dc.date.issued2017
dc.identifier.urihttp://hdl.handle.net/2376/12977
dc.descriptionThesis (Ph.D.), Mechanical Engineering, Washington State Universityen_US
dc.description.abstractCapillary flow is driven or controlled by capillary forces, exerted at the triple line where the fluid phases meet the solid boundary. Phase field (PF) models naturally accommodate diffusive triple line motion with variable contact angle, thus allowing for the no-slip boundary condition without the stress singularities. Moreover, they are uniquely suited for modeling of topological discontinuities which often arise during capillary flows. In this study, we consider diffusive triple line motion within two PF models: the compositionally compressible (CC) and the incompressible (IC) models. We derive the IC model as a systematic approximation to the CC model, based on a suitable choice of continuum velocity field. The CC model, applied to the fluids of dissimilar mass densities, exhibits a computational instability at the triple line. The IC model perfectly represents the analytic equilibria. We develop the parameter identification procedure and show that the triple line kinetics can be well represented by the IC model’s diffusive boundary condition. The IC model is first tested by benchmarking the phase-field and experimental kinetics of water, and silicone oil spreading over the glass plates in which two systems do not interact with the substrate. Then, two high-temperature physical settings involving spreading of the molten Al-Si alloy: one over a rough wetting substrate, the other over a non-wetting substrate are modeled in a T-joint structure which is a typical geometric configuration for many brazing and soldering applications. Surface roughness directly influences the spreading of the molten metal by causing break-ups of the liquid film and trapping the liquid away from the joint. In the early stages of capillary flow over non-wetting surface, the melting and flow are concurrent, so that the kinetics of wetting is strongly affected by the variations in effective viscosity of the partially molten metal. We define adequate time-dependent functions for the variations of Al-Si alloy viscosity and triple line mobility to describe the wetting kinetics.en_US
dc.description.sponsorshipWashington State University, Mechanical Engineeringen_US
dc.languageEnglish
dc.rightsIn copyright
dc.rightsPublicly accessible
dc.rights.urihttp://rightsstatements.org/vocab/InC/1.0/
dc.subjectMechanical engineering
dc.subjectMaterials Science
dc.subjectcomputational instabilities
dc.subjectdiffusive triple line motion
dc.subjectno-slip boundary condition
dc.subjectphase field model
dc.subjectquasi-compressibility
dc.subjectwetting and Spreading
dc.titleCAPILLARY FLOW OF LIQUID METALS IN BRAZING
dc.typeElectronic Thesis or Dissertation


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