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" Sweeping Jet Film Cooling "
Hossain, Mohammad Arif
Bons, Jeffrey
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Latin Dissertation
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| Language of Document
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English
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| Record Number
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1055670
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| Doc. No
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TL54787
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| Main Entry
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Hossain, Mohammad Arif
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| Title & Author
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Sweeping Jet Film Cooling\ Hossain, Mohammad ArifBons, Jeffrey
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| College
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The Ohio State University
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| Date
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2020
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| Degree
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Ph.D.
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| student score
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2020
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| Note
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269 p.
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| Abstract
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Gas turbine is an integrated part of modern aviation and power generation industry. The thermal efficiency of a gas turbine strongly depends on the turbine inlet temperature (TIT), and the turbine designers are continuously pushing the TIT to a higher value. Due to the increased freedom in additive manufacturing, the complex internal and external geometries of the turbine blade can be leveraged to utilize innovative cooling designs to address some of the shortcomings of current cooling technologies. The sweeping jet film cooling has shown some promise to be an effective method of cooling where the coolant can be brought very close to the blade surface due to its sweeping nature. A series of experiments were performed using a row of fluidic oscillators on a flat plate. Adiabatic cooling effectiveness, convective heat transfer coefficient, thermal field, and discharge coefficient were measured over a range of blowing ratios and freestream turbulence. Results were compared with a conventional shaped hole (777-hole), and the sweeping jet hole shows improved cooling performance in the lateral direction. Numerical simulation also confirmed that the sweeping jet creates two alternating vortices that do not have mutual interaction in time. When the jet sweeps to one side of the hole exit, it acts as a vortex generator as it interacts with the mainstream ow. This prevents the formation of the counter-rotating vortex pair (CRVP) and allows the coolant to spread in the lateral direction. The results obtained from the low speed at plate tests were utilized to design the sweeping jet film cooling hole for more representative turbine vane geometry. Experiments were performed in a low-speed linear cascade facility. Results showed that the sweeping jet hole has higher cooling effectiveness in the near hole region compared to the shaped hole at high blowing ratios. Next, a detailed experimental investigation of sweeping jet film cooling on the suction surface of a near engine scale transonic nozzle guide vane at an engine relevant Mach number (Maex = 0.8) and Reynolds number (Rec = 1x10e6) to determine the effect of compressibility. The heat transfer measurements were conducted with a transient IR method, and the convective heat transfer coefficient (HTC) and adiabatic film cooling effectiveness were estimated using a dual linear regression technique (DLRT). Aerodynamic loss measurements were also performed at an exit plane downstream of the vane cascade. Finally, a comprehensive design integration of sweeping jet film hole was carried out in a Direct Metal Laser Sintering (DMLS) enabled engine scale nozzle guide vane and experimental investigation of overall cooling effectiveness at engine relevant temperature conditions were assessed. The systematic evolution of a sweeping jet film cooling hole design from a large scale flat plate to an engine scale nozzle guide vane has been presented.
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| Descriptor
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Aerospace engineering
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Engineering
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Mechanical engineering
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Bons, Jeffrey
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The Ohio State University
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