Film Cooling Research Facilities

Film cooling is primarily used for cooling hot section components in the high-pressure turbine of the gas turbine engine. It is primarily used in the first stage downstream of the combustor where the thermal environment is most hostile to the components.

From the fluids perspective, the flow exiting the combustor is highly-turbulent. Thus, in order to simulate the engine environment in the high-pressure turbine, high turbulence is a necessity. Experimentally, this is accomplished by using a high-turbulence generator to supply the main flow source. The generator used in this research program is shown below. With variable setting of the primary fans and the secondary fan, turbulence levels in the range of 5-20% can be generated.

Turbulence Generator
The High Turbulence Generator

Downstream of the combustor simulator is the film cooling test section. It consists of a film cooling test plate and coolant supply system. Different film cooling test plates and test plate modifications are used to create different cooling flow orientations. Streamwise (coolant flow introduced parallel to the mainstream) and lateral (coolant flow introduced cross-stream to the mainstream) orientations are investigated. Both have an inclination angle of 35 degrees, which is common to film cooling designs. Also, film cooling hole length and plenum variations are imposed to provide additional cooling hole geometries. A photograph of the overall film cooling test facility is provided.

Film Cooling Facility
Our Current High Turbulence Film Cooling Facility

For both of our film cooling geometries (streamwise and lateral), an automatic two axis traversing system is used to collect y-z profiles of fluid velocity, turbulence intensity, and Reynolds shear stresses at the planes shown (see figure below). By the use of automated data collection systems, these profiles can be collected with good precision and fine gridding with very little human effort.

Measurement Planes

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Comments? Questions? Mail to kaszeta@me.umn.edu