Title page for ETD etd-09252003-090901

Type of Document Master's Thesis
Author Knost, Daniel G.
URN etd-09252003-090901
Title Predictions and Measurements of Film-Cooling on the Endwall of a First Stage Vane
Degree Master of Science
Department Mechanical Engineering
Advisory Committee
Advisor Name Title
Thole, Karen A. Committee Chair
Ng, Fai Committee Member
Vick, Brian L. Committee Member
  • gas turbine
  • gas turbine heat transfer
  • endwall
Date of Defense 2003-09-12
Availability unrestricted
In gas turbine development, the direction has been toward higher turbine inlet temperatures to increase the work output and thermal efficiency. This extreme environment can significantly impact component life. One means of preventing component burnout in the turbine is to effectively use film-cooling whereby coolant is extracted from the compressor and injected through component surfaces. One such surface is the endwall of the first stage nozzle guide vane.

This thesis details the design, prediction, and testing of two endwall film-cooling hole patterns provided by leading gas turbine engine companies. In addition a flush, two-dimensional slot was included to simulate leakage flow from the combustor-turbine interface.

The slot coolant was found to exit in a non-uniform manner leaving a large, uncooled ring around the vane. Film-cooling holes were effective at distributing coolant throughout much of the passage, but at low blowing rates were unable to provide any benefit to the critical vane-endwall junction both at the leading edge and along the pressure side. At high blowing ratios, the increased momentum of the jets induced separation at the leading edge and in the upstream portion of the passage along the pressure side, while the jets near the passage exit remained attached and penetrated completely to the vane surface.

Computational fluid dynamics (CFD) was successful at predicting coolant trajectory, but tended to under-predict thermal spreading and jet separation. Superposition was shown to be inaccurate, over-predicting effectiveness levels and thus component life, because the flow field was altered by the coolant injection.

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