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dc.contributor.authorNagy, Peter Takahiroen_US
dc.date.accessioned2007-03-27T18:03:21Z
dc.date.available2007-03-27T18:03:21Z
dc.date.issued2006-11-20en_US
dc.identifier.urihttp://hdl.handle.net/1853/13958
dc.description.abstractA droplet may be prevented from wetting a solid surface by the existence of a lubricating film of air, driven by theromcapillary convection, between liquid and solid surfaces. The noncontact nature and the load-carrying capability of a nonwetting droplet lead to potential engineering applications, e.g., low-friction bearings. The present research consists of two thrusts. The first is aimed at quantifying nonwetting-system failures (film and pinning) triggered by application of a mechanical load, gaining insights to failure mechanisms. Experimental results show that film failure occurs over a wide range of droplet volumes when the temperature difference between the droplet and the plate, the driving potential of the free-surface motion, is small. Interferometric observations reveal flow instability just prior to film failure, with the growth of a nonaxisymmetric disturbance on a free surface (m = 1). Pinning failure becomes more prevalent as the temperature difference is increased, stabilizing the film flow. As part of the present investigation, a system was devised, allowing an oscillating free-surface to be reconstructed from a series of interferograms. The dynamic responses of the free surface reveal mode coupling, with harmonics of the input frequency excited through nonlinearity. The second thrust of the research succeeded in levitating and translating a droplet using the mechanism of permanent nonwetting. In this scheme, the droplet is heated by a CO2 laser and is placed above a cooled glass surface in order to drive the lubricating film that supports the weight of the drop. Furthermore, the position of the droplet can be controlled by moving the heating location, which leads to an asymmetry of the flow fields, driving air from the cooler-end of the droplet and propelling it towards the heat source. These demonstrations suggest the techniques potential use as a liquid-delivery scheme in a Lab-On-a-Chip system. Modeling is carried out to estimate propulsive forces on the droplet and to explain oscillatory behavior observed when excessive heating is applied on the drop. The concept to sandwich a droplet between two plates, a necessary configuration for levitating smaller droplets (less than mm-scale), is also discussed.en_US
dc.format.extent5155252 bytes
dc.format.mimetypeapplication/pdf
dc.language.isoen_US
dc.publisherGeorgia Institute of Technologyen_US
dc.subjectDroplet levitationen_US
dc.subjectNonwettingen_US
dc.subjectThermocapillary convectionen_US
dc.subjectMarangonien_US
dc.subject.lcshMarangoni effecten_US
dc.subject.lcshMachine parts Failuresen_US
dc.subject.lcshLubrication and lubricantsen_US
dc.subject.lcshHeat Convectionen_US
dc.subject.lcshDropsen_US
dc.titleInvestigation of Nonwetting System Failure and System Integrationen_US
dc.typeDissertationen_US
dc.description.degreePh.D.en_US
dc.contributor.departmentMechanical Engineeringen_US
dc.description.advisorCommittee Chair: Neitzel, G. Paul; Committee Member: Glezer, Ari; Committee Member: McCuan, John; Committee Member: Schatz, Michael; Committee Member: Smith, Marc K.en_US


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