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dc.contributor.advisorMorrison, Gerald L.en_US
dc.creatorSuryanarayanan, Saikishanen_US
dc.date.accessioned2010-07-15T00:12:42Zen_US
dc.date.accessioned2010-07-23T21:44:06Z
dc.date.available2010-07-15T00:12:42Zen_US
dc.date.available2010-07-23T21:44:06Z
dc.date.created2009-05en_US
dc.date.issued2010-07-14en_US
dc.date.submittedMay 2009en_US
dc.identifier.urihttp://hdl.handle.net/1969.1/ETD-TAMU-2009-05-556en_US
dc.description.abstractA seal is a component used in a turbomachine to reduce internal leakage of the working fluid and to increase the machine's efficiency. The stability of a turbomachine partially depends upon the rotodynamic coefficients of the seal. The integral control volume based rotodynamic coefficient prediction programs are no more accurate than the accuracy of the leakage mass flow rate estimation. Thus an accurate prediction of the mass flow rate through seals is extremely important, especially for rotodynamic analysis of turbomachinery. For labyrinth seals, which are widely used, the energy dissipation is achieved by a series of constrictions and cavities. When the fluid flows through the constriction (under each tooth), a part of the pressure head is converted into kinetic energy, which is dissipated through small scale turbulence-viscosity interaction in the cavity that follows. Therefore, a leakage flow rate prediction equation can be developed by comparing the seal to a series of orifices and cavities. Using this analogy, the mass flow rate is modeled as a function of the flow coefficient under each tooth and the carry over coefficient, which accounts for the turbulent dissipation of kinetic energy in a cavity. This work, based upon FLUENT CFD simulations, initially studies the influence of flow parameters, in addition to geometry, on the carry over coefficient of a cavity, developing a better model for the same. It is found that the Reynolds number and clearance to pitch ratios have a major influence and tooth width has a secondary influence on the carry over coefficient and models for the same were developed for a generic rectangular tooth on stator labyrinth seal. The discharge coefficient of the labyrinth seal tooth (with the preceding cavity) was found to be a function of the discharge coefficient of a single tooth (with no preceding cavity) and the carry over coefficient. The discharge coefficient of a single tooth is established as a function of the Reynolds number and width to clearance ratio of the tooth and a model for the same is developed. It is also verified that this model describes the discharge coefficient of the first tooth in the labyrinth seal. By comparing the coefficients of discharge of compressible flow to that of incompressible flow at the same Reynolds number, the expansion factor was found to depend only upon the pressure ratio and ratio of specific heats. A model for the same was developed. Thus using the developed models, it is possible to compute the leakage mass flow rate as well as the axial distribution of cavity pressure across the seal for known inlet and exit pressures. The model is validated against prior experimental data.en_US
dc.format.mimetypeapplication/pdfen_US
dc.language.isoengen_US
dc.subjectlabyrinth sealen_US
dc.subjectleakageen_US
dc.subjectCFDen_US
dc.subjectcarry over coefficienten_US
dc.subjectdischarge coefficienten_US
dc.subjectexpansion factoren_US
dc.titleLabyrinth Seal Leakage Equationen_US
dc.typeBooken
dc.typeThesisen
thesis.degree.departmentMechanical Engineeringen_US
thesis.degree.disciplineMechanical Engineeringen_US
thesis.degree.grantorTexas A&M Universityen_US
thesis.degree.nameMaster of Scienceen_US
thesis.degree.levelMastersen_US
dc.contributor.committeeMemberHan, Je C.en_US
dc.contributor.committeeMemberRandall, Robert E.en_US
dc.type.genreElectronic Thesisen_US
dc.type.materialtexten_US


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