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Bidirectional Brush Seals: Post-Test AnalysisA post-test analysis of a set of inside-diameter/outside-diameter (ID/OD) bidirectional brush seals used in three-port wave rotor tests was undertaken to determine brush bristle and configuration wear, pullout, and rotor coating wear. The results suggest that sharp changes in the pressure profiles were not well reflected in bristle tip configuration patterns or wear. Also, positive-to-negative changes in axial pressure gradients appeared to have little effect on the backing plates. Although the brushes had similar porosities, they had very different unpacked arrays. This difference could explain the departure of experimental data from computational fluid dynamics flow predictions for well-packed arrays at higher pressure drops. The rotor wear led to "car-track" scars (upper and lower wear bands) with a whipped surface between the bands. Those bands may have resulted from bristle stiffening at the fence and gap plates during alternate portions of the rotor cycle. Within the bristle response range the wear surface reflected the pressure distribution effect on bristle motion. No sacrificial metallurgical data were taken. The bristles did wear, with correspondingly more wear on the ID brush configurations than on the OD configurations; the complexity in constructing the ID brush was a factor.
Document ID
19980017553
Acquisition Source
Legacy CDMS
Document Type
Technical Memorandum (TM)
Authors
Hendricks, Robert C.
(NASA Lewis Research Center Cleveland, OH United States)
Wilson, Jack
(NYMA, Inc. Brook Park, OH United States)
Wu, Tom Y.
(NASA Lewis Research Center Cleveland, OH United States)
Flower, Ralph
(Cross Mfg. Ltd., Devizes Wiltshire, United Kingdom)
Mullen, Robert L.
(Case Western Reserve Univ. Cleveland, OH United States)
Date Acquired
September 6, 2013
Publication Date
November 1, 1997
Subject Category
Spacecraft Propulsion And Power
Report/Patent Number
NAS 1.15:107501
E-10803
NASA-TM-107501
Meeting Information
Meeting: International Symposium on Transport Phenomena and Dynamics of Rotating Machinery
Location: Honolulu, HI
Country: United States
Start Date: February 22, 1998
End Date: February 26, 1998
Sponsors: United States Turbo and Power Machinery Research Center, Pacific Centre of Thermal Fluids Engineering
Funding Number(s)
PROJECT: RTOP 233-1B-1B
CONTRACT_GRANT: NAS3-27186
Distribution Limits
Public
Copyright
Work of the US Gov. Public Use Permitted.
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