The Effect of Endwall Contouring On Boundary Layer Development in a Turbine Blade Passage

dc.contributor.authorLynch, Stephen P.en
dc.contributor.committeechairThole, Karen A.en
dc.contributor.committeememberSimpson, Roger L.en
dc.contributor.committeememberVlachos, Pavlos P.en
dc.contributor.committeememberO'Brien, Walter F. Jr.en
dc.contributor.committeememberNg, Wing Faien
dc.contributor.departmentMechanical Engineeringen
dc.date.accessioned2017-04-06T15:43:43Zen
dc.date.adate2011-09-22en
dc.date.available2017-04-06T15:43:43Zen
dc.date.issued2011-08-31en
dc.date.rdate2016-10-07en
dc.date.sdate2011-09-13en
dc.description.abstractIncreased efficiency and durability of gas turbine components is driven by demands for reduced fuel consumption and increased reliability in aircraft and power generation applications. The complex flow near the endwall of an axial gas turbine has been identified as a significant contributing factor to aerodynamic loss and increased part temperatures. Three-dimensional (non-axisymmetric) contouring of the endwall surface has been shown to reduce aerodynamic losses, but the effect of the contouring on endwall heat transfer is not well understood. This research focused on understanding the general flow physics of contouring and the sensitivity of the contouring to perturbations arising from leakage features present in an engine. Two scaled low-speed cascades were designed for spatially-resolved measurements of endwall heat transfer and film cooling. One cascade was intended for flat and contoured endwall studies without considering typical engine leakage features. The other cascade modeled the gaps present between a stator and rotor and between adjacent blades on a wheel, in addition to the non-axisymmetric endwall contouring. Comparisons between a flat and contoured endwall showed that the contour increased endwall heat transfer and increased turbulence in the forward portion of the passage due to displacement of the horseshoe vortex. However, the contour decreased heat transfer further into the passage, particularly in regions of high heat transfer, due to delayed development of the passage vortex and reduced boundary layer skew. Realistic leakage features such as the stator-rotor rim seal had a significant effect on the endwall heat transfer, although leakage flow from the rim seal only affected the horseshoe vortex. The contours studied were not effective at reducing the impact of secondary flows on endwall heat transfer and loss when realistic leakage features were also considered. The most significant factor in loss generation and high levels of endwall heat transfer was the presence of a platform gap between adjacent airfoils.en
dc.description.degreePh. D.en
dc.identifier.otheretd-09132011-231220en
dc.identifier.sourceurlhttp://scholar.lib.vt.edu/theses/available/etd-09132011-231220/en
dc.identifier.urihttp://hdl.handle.net/10919/77202en
dc.language.isoen_USen
dc.publisherVirginia Techen
dc.rightsIn Copyrighten
dc.rights.urihttp://rightsstatements.org/vocab/InC/1.0/en
dc.subjectFilm Coolingen
dc.subjectTurbine Blade Endwallsen
dc.subjectThree-Dimensional Boundary Layersen
dc.titleThe Effect of Endwall Contouring On Boundary Layer Development in a Turbine Blade Passageen
dc.typeDissertationen
dc.type.dcmitypeTexten
thesis.degree.disciplineMechanical Engineeringen
thesis.degree.grantorVirginia Polytechnic Institute and State Universityen
thesis.degree.leveldoctoralen
thesis.degree.namePh. D.en

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