Metal CMC Joining for Arbitrarily Sized Scramjet Assemblies

Physical Sciences Inc. (PSI) will produce dissimilar material scramjet duct segments coupled together using engineered conical sealing surfaces and a PSI-developed rope seal. Prior work by PSI has shown the ability to design and fabricate conical sealing interfaces with lower permeability and higher survivability than the incumbent technology. The focus of this research effort will be to develop flight-weight joints between engine segments of dissimilar materials to replace existing joining techniques. Existing joints cannot accommodate defects or distortions outside of machining tolerances, so they are at risk of distortion and leakage. Current seals are only viable up to about 1800 °F, which will not be adequate for high speed engines in the future. PSI’s joint accommodates thermal expansion, component erosion, and manufacturing defects using an engineered geometry that allows the seal to remain in contact despite very coarse tolerances. Further increasing reliability, our rope seals are highly resilient and resistant to oxidation at higher temperatures. PSI has demonstrated long-duration capability of the joint and seal in Phase I, compatible with high-speed engines applications. In the proposed Phase II, PSI will demonstrate the suitability of the joint-and-seal in direct-connect scramjet ground test by delivering testable hardware to the Air Force by the end of the program.