CMCs are typically made of silicon carbide ceramic fibers and ceramic resin, and are further enhanced with proprietary coatings. CMC development is a key initiative at GE Aviation, and an enabling technology in several of GE’s private and government-funded engine demonstrator programs now underway. CMC components also are a key feature of GE’s eCore program, the cornerstone for the company’s next-generation of jet engines for narrow-body regional and business jets because of their low mass and greater durability and heat resistance, compared to metals. These characteristics mean engines need less cooling air, which improves overall engine efficiency. GE Aviation produces CMC parts at its facility in Newark, Del.
Schafrik predicts CMC parts will populate many areas in the engine’s hot section, including high- and low-pressure turbine vanes and blades, turbine shrouds, and combustor liners. For example, CFM International, a 50/50 joint venture of Snecma and GE, will run a Leap-X demonstrator engine in 2010 with CMC components, in pursuit of technologies for next-generation engines for narrow-body aircraft.
GE Aviation pioneered the use of composites in the “cold section” of jet engines in 1995, introducing the first composite front fan blade (a carbon/epoxy construction) in its GE90 engine, which powers the Boeing 777. In its new GEnx engine, developed for the Boeing 787, GE will use similar composite fan blades, and introduce a braided-fiber composite fan blade containment case. Both will provide dramatic weight savings. CMC combustor liners are under consideration for future GEnx production models.