Ephraim Gutmark
Paul Orkwis
And Students from the University of Cincinnati
Balu Sekar
Marc Polanka
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Ephraim Gutmark |
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Experimental and Computational Research on the Effect of Combustion Product Interaction with Vane Film Cooling Flow for High Fuel-Air Ratio Operation The operating temperatures of gas turbine engines have continued to increase as a means to improve performance. Cycle efficiency and exhaust jet velocity are just two important factors that benefit from increased operating temperatures. Reducing the engine weight has also been a goal. Recent civilian and military engines attempt to combine the two by employing more aggressive blade loading (to reduce stage count, i.e., weight) while at the same time increasing combustor exit temperature. To accommodate this trend, engineers continue to search for more effective cooling techniques that provide improved cooling with reduced coolant mass flow requirements. A frequently used approach is the application of jets to provide a coolant film between the hot gas path and the blade surface. This creates a delicate balance since coolant air is taken from the compressor, which adversely affects the engine cycle. To complicate matters, it is not always the case that increased coolant mass flow results in enhanced cooling effectiveness because of effects like jet blow off and pairing. To understand this problem better there have been and continues to be a considerable body of research aimed at unlocking the physics that control the jets used in film cooling applications. In this poster, rig tests and numerical analysis are reported to evaluate the performance of a specific film cooling arrangement on an unloaded blade with the blowing ratio, mainstream turbulence level and turbulent length scale are changed. Simulations were run for a range of overall blowing ratios of 0.67, 1.02, 1.4; mainstream turbulence intensities, 1%, 10% and 20%; and reduced turbulent length scale (40%) for 10% turbulence intensity. The experimental rig is also shown with details and show thermal paint results for the temperature distribution on the vane blade. The poster illustrates the numerical procedure employed in this work, including the geometry of the test article, the rig and the boundary conditions imposed on the simulation. Results are then presented for cooled cases with three blowing ratios and three turbulence intensities and the 40% length scale 10% turbulence intensity case. The poster illustrates the plan of the rig tests and discuss summary of the obtained results.
Dr. Ephraim Gutmark and Dr. Paul Orkwis and Students,
University of Cincinnati |