GLTRS--Glenn
TITLE AND SUBTITLE:
High Temperature Propulsion System Structural Seals for Future Space Launch Vehicles

AUTHOR(S):
Patrick H. Dunlap, Jr., Bruce M. Steinetz, and Jeffrey J. DeMange

REPORT DATE:
January 2004

FUNDING NUMBERS:
WBS-22-794-20-6S

PERFORMING ORGANIZATION NAME(S) AND ADDRESS(ES):
National Aeronautics and Space Administration
John H. Glenn Research Center at Lewis Field
Cleveland, Ohio 44135-3191

PERFORMING ORGANIZATION REPORT NUMBER:
E-14304

SPONSORING/MONITORING AGENCY NAME(S) AND ADDRESS(ES):
National Aeronautics and Space Administration
Washington, DC 20546-0001

REPORT TYPE AND DATES COVERED:
Technical Memorandum

SPONSORING/MONITORING AGENCY REPORT NUMBER:
NASA TM-2004-212907

SUPPLEMENTARY NOTES:
Prepared for the 39th Combustion/27th Airbreathing Propulsion/21st Propulsion Systems Hazards/3rd Modeling and Simulation Joint Subcommittee Meeting sponsored by the Joint Army-Navy-NASA-Air Force (JANNAF) Interagency Propulsion Committee, Colorado Springs, Colorado, December 1-5, 2003. Patrick H. Dunlap and Bruce M. Steinetz, NASA Glenn Research Center; and Jeffrey J. DeMange, University of Toledo, Toledo, Ohio 43606. Responsible person, Patrick H. Dunlap, organization code 5950, 216-433-3017.

ABSTRACT:
Durable, flexible sliding seals are required in advanced hypersonic engines to seal the perimeters of movable engine ramps for efficient, safe operation in high heat flux environments at temperatures of 2000 to 2500 °F. Current seal designs do not meet the demanding requirements for future engines, so NASA's Glenn Research Center is developing advanced seals and preloading devices to overcome these shortfalls. An advanced ceramic wafer seal design and two types of seal preloading devices were evaluated in a series of compression, scrub, and flow tests. Silicon nitride wafer seals survived 2000 in. (1000 cycles) of scrubbing at 1600 °F against an Inconel 625 rub surface with no chips or signs of damage. Flow rates measured for the wafers before and after scrubbing were almost identical and were up to 32 times lower than those recorded for the best braided rope seal flow blockers. Canted coil springs and silicon nitride compression springs showed promise conceptually as potential seal preloading devices to help maintain seal resiliency. A finite element model of the canted coil spring revealed that it should be possible to produce a spring out of high temperature materials for applications at 2000+ °F.

SUBJECT TERMS:
Seals; Flow; Design; Test; High temperature

NUMBER OF PAGES:
25

PDF AVAILABLE FROM URL:
2004/TM-2004-212907.pdf ( 2,425 KB )
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