Publication Date

2018

Document Type

Thesis

Committee Members

Christopher Marks (Committee Member), Rolf Sondergaard (Committee Member), Mitch Wolff (Advisor)

Degree Name

Master of Science in Mechanical Engineering (MSME)

Abstract

High-lift low-pressure turbine blades produce significant losses at the junction with the endwall. The losses are caused by several complex three-dimensional vortical flow structures, which interact with the blade suction surface boundary layer. This study investigates the unsteady characteristics of these endwall flow structures on a highly loaded research profile and the adjacent endwall using surface-mounted hot-film sensors. Experiments were conducted in a low-speed linear cascade wind tunnel. The front-loaded blade profile was subjected to three different inlet conditions, consisting of two turbulence levels, and three incoming boundary layer thicknesses. Multiple surface-mounted hot-film sensors were installed throughout the passage. This thesis progressed in three stages of research. The first verified that the hot-film sensors could be used to detect flow structures in the cascade. The second used the results from installed hot-films to examine the unsteady characteristics of vortices formed near the leading edge and the propagation of the passage vortex across the passage where it interacts with a corner separation along the suction surface. Simultaneous measurements from the hot-film sensors were analyzed for frequency spectra and time lag in order to provide new insight into the endwall flow dynamics. Finally, signatures from the hot-films were linked to specific flow phenomena through concurrent flow visualization. At each stage of the investigation, results were compared to the results of a numerical simulation.

Page Count

95

Department or Program

Department of Mechanical and Materials Engineering

Year Degree Awarded

2018


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