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Variable-Speed Power-Turbine Research at Glenn Research CenterThe main rotors of the NASA Large Civil Tilt-Rotor (LCTR) notional vehicle operate over a wide speed-range, from 100 percent at takeoff to 54 percent at cruise. The variable-speed power turbine (VSPT) offers one approach by which to effect this speed variation. VSPT aerodynamics challenges include high work factors at cruise, wide (40 to 60 ) incidence-angle variations in blade and vane rows over the speed range, and operation at low Reynolds numbers. Rotordynamics challenges include potential responsiveness to shaft modes within the 50 percent VSPT speed-range. A research effort underway at NASA Glenn Research Center, intended to address these key aerodynamic and rotordynamic challenges, is described. Conceptual design and 3-D multistage RANS and URANS analyses, conducted internally and under contract, provide expected VSPT sizing, stage-count, performance and operability information, and maps for system studies. Initial steps toward experimental testing of incidence-tolerant blading in a transonic linear cascade are described, and progress toward development/improvement of a simulation capability for multistage turbines with low Reynolds number transitional flow is summarized. Preliminary rotordynamics analyses indicate that viable concept engines with 50 percent VSPT shaft-speed range. Assessments of potential paths toward VSPT component-level testing are summarized.
Document ID
Document Type
Technical Memorandum (TM)
Welch, Gerard E. (NASA Glenn Research Center Cleveland, OH, United States)
McVetta, Ashlie B. (NASA Glenn Research Center Cleveland, OH, United States)
Stevens, Mark A. (NASA Glenn Research Center Cleveland, OH, United States)
Howard, Samuel A. (NASA Glenn Research Center Cleveland, OH, United States)
Giel, Paul W. (ASRC Aerospace Corp. Cleveland, OH, United States)
Ameri, Ali, A. (Ohio State Univ. Columbus, OH, United States)
To, Waiming (Toledo Univ. Toledo, OH, United States)
Skoch, Gary J. (Army Research Lab. Cleveland, OH, United States)
Thurman, Douglas R. (Army Research Lab. Cleveland, OH, United States)
Date Acquired
August 26, 2013
Publication Date
July 1, 2012
Subject Category
Report/Patent Number
Funding Number(s)
WBS: WBS 877868.
Distribution Limits
Public Use Permitted.

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