Type of Document Dissertation Author Knost, Daniel G Author's Email Address firstname.lastname@example.org URN etd-09302008-202855 Title Parametric Investigation of the Combustor-Turbine Interface Leakage Geometry Degree PhD Department Mechanical Engineering Advisory Committee
Advisor Name Title Thole, Karen A. Committee Chair Ball, Kenneth S. Committee Co-Chair Duggleby, Andrew T. Committee Member Ng, Fai Committee Member Stremler, Mark A. Committee Member Keywords
- secondary flows
- endwall cooling
- gas turbine
Date of Defense 2008-09-19 Availability unrestricted AbstractEngine development has been in the direction of increased turbine inlet
temperatures to improve efficiency and power output. Secondary flows develop
as a result of a near-wall pressure gradient in the stagnating flow approaching
the inlet nozzle guide vane as well as a strong cross-passage gradient within the
passage. These flow structures enhance heat transfer and convect hot core flow
gases onto component surfaces. In modern engines it has become critical to cool
component surfaces to extend part life.
Bypass leakage flow emerging from the slot between the combustor and
turbine endwalls can be utilized for cooling purposes if properly designed. This
study examines a three-dimensional slot geometry, scalloped to manipulated
leakage flow distribution. Statistical techniques are used to decouple the effects
of four geometric parameters and quantify the relative influence of each on
endwall cooling levels and near-wall total pressure losses. The slot geometry is
also optimized for robustness across a range of inlet conditions.
Average upstream distance to the slot is shown to dominate overall cooling
levels with nominal slot width gaining influence at higher leakage flow rates.
Scalloping amplitude is most influential to near-wall total pressure loss as formation
of the horseshoe vortex and cross flow within the passage are affected.
Scalloping phase alters local cooling levels as leakage injection is shifted laterally
across the endwall.
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