EVENDALE, OHIO –– Component testing of the TAPS III (twin-annular pre-mixing swirler) combustor for the GE9X engine for the Boeing 777X is demonstrating promising results. 

The GE9X TAPS III combustor is a unique third-generation combustion system that pre-mixes air and fuel prior to combustion for leaner burn and fewer emissions than conventional combustion systems. The TAPS combustion was introduced on the GEnx engine for the Boeing 787 Dreamliner and the 747-8 aircraft and was enhanced for the TAPS II combustor in CFM International's LEAP engine for narrowbody aircraft.

"The TAPS III combustor for the GE9X takes combustion technology to the next level," said Bill Millhaem, general manager of the GE90/GE9X engine programs. "Since 2011, GE engineers have been working the GE9X TAPS III combustor. The TAPS III combustor will feature fuel nozzle tips manufactured using additive technology, along with a new combustor dome design and ceramic matrix composite (CMC) inner and outer liners, which will improve durability and require less cooling air to enhance the lean-burn combustion process."

To design the world-class, low-emissions combustor, GE engineers successfully matched the combustion system to the GE9X's 27:1 pressure ratio, which is the highest pressure ratio of any GE engine. The GE9X team utilized new technologies and materials that require less cooling air while allowing more air into the mixer. The additional air in the mixer helps reduce emissions by creating a leaner burn, which will enable the GE9X to have a 30% margin to CAEP/8 standards for NOx. 

Component testing of the TAPS III combustor began in 2012. This September, a full annular rig combustor test successfully demonstrated the material capabilities of the CMC combustor liners, which will be the first continuous CMC combustor liners in a commercial jet engine. The liners were tested at dynamic loading levels well beyond what it will experience in service. Additional full annular rig testing, including GEnx- and GE9X-scale combustors, will be conducted during the next two years. 

Other future combustor tests include a GE9X combustor sector rig that will run in GE's new $100 million, 20,000 square foot combustion test cell under construction in Evendale, Ohio. With a 200-foot-tall stainless steel exhaust stack, the test cell is scheduled to be completed next year, with three parallel test stands for single-cup and sector testing. The test cell will be a one-of-a-kind facility with the capability to push test conditions beyond the GE9X cycle. 

GE will spend more than $300 million on technology maturation testing for the new GE9X engine in 2014. This year's testing included additional high-pressure compressor testing in Massa, Italy, to demonstrate additional specific fuel consumption improvement, and the universal propulsion simulator (UPS) fan performance and acoustic tests at Boeing's Seattle, Washington, UPS test cell. By year end, GE Aviation will start ground testing of a GEnx engine incorporating CMCs in both the high-pressure turbine and combustor areas as part of the GE9X technology maturation program.

The GE9X engine will be in the 100,000 pound thrust class. Key features include a 133-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. 

Almost 700 GE9X engines have been ordered by customers since it was launched on the Boeing 777X aircraft last year.

The first demonstration core test is scheduled for 2015. The first engine will test in 2016 with flight-testing on GE's flying testbed anticipated in 2017. Engine certification is scheduled for 2018.

IHI Corporation, Snecma and Techspace Aero (Safran), and MTU Aero Engines AG are participants in the GE9X engine program.

GE Aviation, an operating unit of GE (NYSE: GE), is a world-leading provider of jet and turboprop engines, components and integrated systems for commercial and military aircraft. GE Aviation has a global service network to support these offerings.