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Toward Cooling Uniformity: Investigation of Spiral, Sweeping Holes, and Unconventional Cooling ParadigmsSurface infrared thermography, hotwire anemometry, and thermocouple surveys were performed on two new film cooling hole geometries: spiral/rifled holes and fluidic sweeping holes. Ways to quantify the efficacy of novel cooling holes that are asymmetric, not uniformly spaced or that show variation from hole to hole are presented. The spiral holes attempt to induce large-scale vorticity to the film cooling jet as it exits the hole to prevent the formation of the kidney shaped vortices commonly associated with film cooling jets. The fluidic sweeping hole uses a passive in-hole geometry to induce jet sweeping at frequencies that scale with blowing ratios. The spiral hole performance is compared to that of round holes with and without compound angles. The fluidic hole is of the diffusion class of holes and is therefore compared to a 777 hole and square holes. A patent-pending spiral hole design showed the highest potential of the nondiffusion type hole configurations. Velocity contours and flow temperature were acquired at discreet cross-sections of the downstream flow field. The passive fluidic sweeping hole shows the most uniform cooling distribution but suffers from low span-averaged effectiveness levels due to enhanced mixing. The data was taken at a Reynolds number of 11,000 based on hole diameter and freestream velocity. Infrared thermography was taken for blowing ratios of 1.0, 1.5, 2.0, and 2.5 at a density ratio of 1.05. The flow inside the fluidic sweeping hole was studied using 3D unsteady RANS. A section on ideas for future work is included that addresses issues of quantifying cooling uniformity and provides some ideas for changing the way we think about cooling such as changing the direction of cooling or coupling acoustic devices to cooling holes to regulate frequency.
Document ID
20180002378
Acquisition Source
Glenn Research Center
Document Type
Technical Memorandum (TM)
Authors
Shyam, Vikram (NASA Glenn Research Center Cleveland, OH, United States)
Thurman, Douglas R. (Army Research Lab. Cleveland, OH, United States)
Poinsatte, Philip E. (NASA Glenn Research Center Cleveland, OH, United States)
Ameri, Ali A. (Ohio State Univ. Columbus, OH, United States)
Culley, Dennis E. (NASA Glenn Research Center Cleveland, OH, United States)
Date Acquired
April 11, 2018
Publication Date
March 1, 2018
Subject Category
Fluid Mechanics And Thermodynamics
Statistics And Probability
Instrumentation And Photography
Report/Patent Number
NASA/TM-2018-219763
E-19475
GRC-E-DAA-TN52180
Funding Number(s)
CONTRACT_GRANT: NNC12BA01B
WBS: WBS 081876.02.03.50.04.02
Distribution Limits
Public
Copyright
Public Use Permitted.

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