Rudder/Fin Seal Investigations for the X-38 Re-Entry Vehicle

TITLE AND SUBTITLE:
Rudder/Fin Seal Investigations for the X-38 Re-Entry Vehicle

AUTHOR(S):
Patrick H. Dunlap, Jr., Bruce M. Steinetz, and Donald M. Curry

REPORT DATE:
November 2000

FUNDING NUMBERS:
WU-505-23-0U-00

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-12384

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-2000-210338-REV1
AIAA-2000-3508

SUPPLEMENTARY NOTES:
Prepared for the 36th Joint Propulsion Conference and Exhibit cosponsored by AIAA, ASME, SAE, and ASEE,
Huntsville, Alabama, July 16-19, 2000. Patrick H. Dunlap, Jr. and Bruce M. Steinetz, NASA Glenn Research Center; and Donald M. Curry, NASA Johnson Space Center. Responsible person, Patrick H. Dunlap, Jr., organization code 5950, 216-433-6374.

ABSTRACT:
NASA is currently developing the X-38 vehicle that will be used to demonstrate the technologies required for a crew return vehicle (CRV) for the International Space Station. The X-38 control surfaces require high temperature seals to limit hot gas ingestion and transfer of heat to underlying low-temperature structures to prevent over-temperature of these structures and possible loss of the vehicle.
This paper presents results for thermal analyses and flow and compression tests conducted on as-received and thermally exposed seals for the rudder/fin location of the X-38. A thermal analysis of the rudder/fin dual seal assembly based on representative heating rates on the windward surface of the rudder/fin area predicted a peak seal temperature of 1900慚. The temperature-exposed seals were heated in a compressed state at 1900慚 corresponding to the predicted peak temperature. Room temperature compression tests were performed to determine load versus linear compression, preload, contact area, stiffness, and resiliency characteristics for the as-received and temperature-exposed seals. Temperature exposure resulted in permanent set and loss of resiliency in these seals. Unit loads and contact pressures for the seals were below the 5 lb/in. and 10 psi limits set to limit the loads on the Shuttle thermal tiles that the seals seal against in the rudder/fin location. Measured seal flow rates for a double seal were about 4.5 times higher than the preliminary seal flow goal. The seal designs examined in this study are expected to be able to endure the high temperatures that they will be exposed to for a single-use life. Tests performed herein combined with future analyses, arc jet tests, and scrubbing tests will be used to select the final seal design for
this application.

SUBJECT TERMS:
Seals; Flow; Design; Test; Re-entry vehicle

NUMBER OF PAGES:
22

PDF AVAILABLE FROM URL:
2000/TM-2000-210338-REV1.pdf
( 405 KB )

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