Measurements and Predictions of Heat Transfer for a First Vane Design

Turbine manufacturers continually seek to gain efficiency by increasing operating temperatures well above the maximum temperature of component alloys. This increase in temperature must be accounted for in the cooling of components by examining the heat transfer from these crucial components. This study specifically examines the effect of a contoured endwall on the heat transfer of a scaled-up stator vane. Understanding the three-dimensional effects of contoured endwalls on vane heat transfer can lead to prolonging blade life. The results of a combined experimental and computational study of heat transfer along the surface of a turbine vane that incorporates a contoured endwall are discussed in detail. A commercially available computational fluid dynamics code was used to design a contoured endwall and simulate an engine representative pressure distribution for a turbine vane cascade placed in a low-speed wind tunnel. A significant flow acceleration caused by the contour increased heat transfer over 40% of the vane span compared to the vane far from the contoured endwall. The effects of freestream turbulence with respect to the contour were examined. Results showed a significant increase in heat transfer at elevated freestream turbulence levels at each span location. The effects of the contour were minimal compared to the effects of increased turbulence. The boundary layer transition location moved further upstream with increasing turbulence. Trip wires were used to model the effect of film-cooling holes on the boundary layer development. The heat transfer increased locally at the trip and either remained elevated if the boundary layer remained turbulent or the heat transfer decreased as the boundary layer relaminarized due to flow acceleration. These results are beneficial to turbine manufacturers interested in effective placement of film-cooling holes.

Name thesis:degree_name

Master of Science

Level thesis:degree_level

masters

Discipline thesis:degree_discipline

Mechanical Engineering

Department dc:contributor.department

Mechanical Engineering

Grantor dc:publisher

Virginia Tech

Year dc:date.issued

2004

Author dc:creator

• Gratton, Andrew Robert

Chair dc:contributor.committeechair

• Thole, Karen A.

Committee members dc:contributor.committeemember

• Vick, Brian L.
• Ng, Fai

• gas turbines
• Heat--Transmission

Statement dc:rights

• In Copyright

Licence dc:rights.uri

• http://rightsstatements.org/vocab/InC/1.0/

Dc Identifier Other

etd-01082004-161821

OAI identifier oai:identifier

oai:vtechworks.lib.vt.edu:10919/30854