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Aerodynamic Effects of High Turbulence Intensity on a Variable-Speed Power-Turbine Blade With Large Incidence and Reynolds Number VariationsThe effects of high inlet turbulence intensity on the aerodynamic performance of a variable speed power turbine blade are examined over large incidence and Reynolds number ranges. These results are compared to previous measurements made in a low turbulence environment. Both high and low turbulence studies were conducted in the NASA Glenn Research Center Transonic Turbine Blade Cascade Facility. The purpose of the low inlet turbulence study was to examine the transitional flow effects that are anticipated at cruise Reynolds numbers. The current study extends this to LPT-relevant turbulence levels while perhaps sacrificing transitional flow effects. Assessing the effects of turbulence at these large incidence and Reynolds number variations complements the existing database. Downstream total pressure and exit angle data were acquired for 10 incidence angles ranging from +15.8deg to −51.0deg. For each incidence angle, data were obtained at five flow conditions with the exit Reynolds number ranging from 2.12×10(exp 5) to 2.12×10(exp 6) and at a design exit Mach number of 0.72. In order to achieve the lowest Reynolds number, the exit Mach number was reduced to 0.35 due to facility constraints. The inlet turbulence intensity, Tu, was measured using a single-wire hotwire located 0.415 axial-chord upstream of the blade row. The inlet turbulence levels ranged from 8 to 15 percent for the current study. Tu measurements were also made farther upstream so that turbulence decay rates could be calculated as needed for computational inlet boundary conditions. Downstream flow field measurements were obtained using a pneumatic five-hole pitch/yaw probe located in a survey plane 7 percent axial chord aft of the blade trailing edge and covering three blade passages. Blade and endwall static pressures were acquired for each flow condition as well. The blade loading data show that the suction surface separation that was evident at many of the low Tu conditions has been eliminated. At the extreme positive and negative incidence angles, the data show substantial differences in the exit flow field. These differences are attributable to both the higher inlet Tu directly and to the thinner inlet endwall boundary layer that the turbulence grid imposes.
Document ID
20140012765
Acquisition Source
Glenn Research Center
Document Type
Technical Memorandum (TM)
Authors
Flegel, Ashlie B. (NASA Glenn Research Center Cleveland, OH, United States)
Giel, Paul W. (Vantage Partners, LLC Brook Park, OH, United States)
Welch, Gerard E. (NASA Glenn Research Center Cleveland, OH, United States)
Date Acquired
October 2, 2014
Publication Date
September 1, 2014
Subject Category
Aerodynamics
Report/Patent Number
NASA/TM-2014-218137
E-18952-1
Meeting Information
Meeting: AIAA Joint Propulsion Conference
Location: Cleveland, OH
Country: United States
Start Date: July 28, 2014
End Date: July 30, 2014
Sponsors: American Inst. of Aeronautics and Astronautics, Society of Automotive Engineers, Inc., American Society for Electrical Engineers, American Society of Mechanical Engineers
Funding Number(s)
WBS: WBS 380046.02.03.02.01.01
Distribution Limits
Public
Copyright
Public Use Permitted.

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