1. • Three designs were examined:
• Rubber Boot Seal
• Expansion Joint
• Iris Seal with Actuator
• Expansion joints can be custom made to
handle extreme temperatures, have high
yield stresses, and incredible strengths.
• Rubber boot seals have been seen as
unreliable due to tears in J-2X testing.
• Iris Seal required further research and
testing.
• Exploration Upper Stage (EUS) will be the
second stage of Blocks 1B and 2
configurations of the Space Launch System
(SLS)
• EUS will be tested in a vacuum through the
use of a diffuser.
• The task of this project was to explore
alternative technologies for sealing the gap
between the engines and the diffuser.
• The emphasis of the project was to
determine methods for joining and sealing
the engines (RL-10) and the diffusers
through research on past diffuser testing
and clamshell seal designs.
• Research seal designs along with their
design stresses, strengths, spring rates, and
temperatures.
• Determine which sealing technology or
method is the best option, if possible.
Acknowledgements: Tom Jacks, Nicholas Nugent, Harry Ryan, Jody Woods, Timothy Miller, Richard Wear, Rebecca Junell, Ana Martinovic
Top Picture: https://www.genuineapplianceparts.com/item_images/DC64-00802A.jpg
Middle Picture: Creo Design of the Expansion Joint with Nozzle by Erick Castillon
Bottom Pictures: Creo Design of Iris Seal and Actuator by Timothy Miller with consent
• Alternative sealing methods were reviewed
for testing of the EUS in a diffuser through
research.
• Expansion joints were found to be a viable
alternative.
• However, further research is needed on the
Iris Seal and Actuator concept.
The Clamshell Seal focuses on using a sealing method to maintain a vacuum within a diffuser while not allowing any pressure loss during high-altitude testing. At the same time, the seal must be able to last several tests before replacement and
without failure along with having the capability of translating with the engine as it undergoes thermal expansion and gimballing. Extensive research on several sealing methods was conducted which eventually led to the selection of three options
that were viewed as promising, suitable, and feasible. After several weeks of research, the best clamshell sealing method for the upcoming testing of the Exploration Upper Stage (EUS) and for future tests was determined to be the use of a
custom-made expansion joint from a vendor because of its high life expectancy, availability, high spring rates in any direction and capability of operating in extreme temperatures, pressures, stresses and loads. It was also concluded that extensive
research must be conducted on the iris seal method as it may serve as a convenient sealing method while having no loads on the engine itself. Nevertheless, the expansion joint is the preeminent option for high-altitude testing with a diffuser for
the upcoming testing of the EUS on the B-2 Test Stand.
Clamshell Seal Methods and Designs
EW-2016-05-00023-SSC
Introduction
Objectives
Outcomes
Summary
Erick Castillon
University of Texas at San Antonio
yzl726@utsa.edu
Clamshell Seal Designs
Rubber Boot Seal
Expansion Joint
Iris Seal and Actuator