Ground testing has started on a GEnx engine that contains ceramic matrix composite (CMC) components in the high-pressure turbine (HPT) and combustor as part of the technology maturation program for the GE9X engine destined to power the Boeing 777X, GE announced Tuesday.
“For the GE9X, GE is applying its extensive knowledge of CMCs to the engine’s hot section,” said Bill Millhaem, general manager of the GE90/GE9X engine programs. “The GEnx engine testing campaign, which began in late January, will allow us to demonstrate the functionality and durability of the full suite of CMC hot section components and help the team lock down the final design for the new GE9X engine by mid-2015.”
The GEnx engine on test at GE’s Peebles, Ohio testing facility contains inner and outer combustor liners, high-pressure turbine (HPT) stage 1 shrouds and stage 2 nozzles. GE plans to test CMC HPT stage 1 nozzles with the demo engine’s second build.
Other, non-CMC parts for the GE9X under evaluation include the next-generation HPT stage 1 blades with new cooling technology and low-pressure turbine titanium aluminide (TiAl) blades produced at Avio Aero, a GE Aviation business, using a new 3-D additive manufacturing process.
The GEnx engine has undergone more than 350 endurance cycles so far as part of the demo testing.
CMCs consist of silicon carbide ceramic fibers and ceramic resin, enhanced with proprietary coatings. More durable than metal, CMC components contain one-third the density of typical metallic parts, making them lighter and longer-lasting. Also more heat-resistant than metals, the material requires 20 percent less cooling air, which improves overall engine efficiency.
GE Aviation’s facility in Newark, Delaware, has mastered the manufacturing process for CMCs in its laboratory, and plans call for GE’s newly opened Asheville, North Carolina factory to become the first involved in the mass production of CMC components.
GE and its partners expect to spend more than $500 million on technology maturation and product development for the new GE9X engine this year. Along with the CMC demo testing, schedules call for this year’s technology maturation testing to include additional high-pressure compressor testing and the first demonstration core test.
The GE9X engine will occupy the 100,000-pound-thrust class. Key features include a 134-inch diameter composite fan case and 16 composite fan blades; a next-generation 27:1 pressure-ratio 11-stage high-pressure compressor; a third-generation TAPS III combustor for high efficiency and low emissions; and CMC material in the combustor and turbine.
GE has collected orders for almost 700 GE9X engines since its launch on the Boeing 777X last year. It expects to conduct the first full engine test next year
and start flight testing in 2017, in time for scheduled certification in 2018.