In the proposed program, MR&D seeks to demonstrate the manufacturability of domestically available, needled Lyocell based Carbon-Carbon (C/C) materials for use in nozzle extension (NE) and exit cone applications. This will be accomplished though a design and analysis trade study, coupled with the fabrication and testing of nozzle extension subcomponent, ultimately improving the Technical Readiness Level (TRL) of needled Lyocell C/C, advancing the State of the Art (SOA) in domestically available C/C.
In the past decade, a number of NASA projects have been aimed at improving the capability and readiness of domestically available C-C for use as a viable candidate for a nozzle extension. Currently, the SOA in use on various launch vehicles is comprised of high temperature (up to 2100°F) capable, nickel based alloys and foreign made C/C composites. Lyocell-based carbon cloth composites continue to be a leading candidate in the quest for a domestically available C/C material. Fabrication of carbonized cloth using Lyocell fiber involves only U.S. suppliers. Lyocell fiber is an environmentally-friendly fiber that produces no harmful byproducts, and whose main ingredient (cellulose) is readily obtained from managed tree farms. Carbonized Lyocell fabric has the same carbon yield and fabric strengths as historic rayon-based materials.
In the proposed program, MR&D aims to demonstrate that combining the inherently desirable properties of the Lyocell carbon fiber (i.e. “high” CTE, low modulus of elasticity) with a needling process results in a domestically available C/C NE and exit cone material that has attractive properties for joining the composite to metallic engine components. This will be accomplished though a design and analysis trade study, coupled with the fabrication and testing of nozzle extension subcomponent.
NASA has an opportunity to further development of domestic capability in producing C‐C nozzles, nozzle extensions, and exit cones. Today, the dominant supplier for parts of this type is Safran Ceramics (formerly Herecles and Snecma Propulsion Solide), based in Bordeaux, France. The United States, when rayon‐based carbon fiber was readily available, was the country of origin for almost all of the world’s C‐C nozzles, nozzle extensions, and exit cones. Lyocell carbon is the leading candidate to replace rayon for these applications.
Successful demonstration of needled Lyocell C/C for nozzle extension and exit applications will serve to benefit any propulsion application within the DOD. The MDA has invested on a number of programs to qualify Lyocell C/Ph and Lyocell C/SiC. Demonstration of needled Lyocell C/C will expand the temperature capabilities enabling domestic availability for future propulsion systems.