Engineering news
GE Aviation has begun ground testing the world’s largest commercial jet engine, which will power the next-generation Boeing 777X.
The GE9X engine spans 3.35m and can generate 100,000 lb of thrust – although its predecessor, the GE90-115B, reached
127,500 lb. GE has received orders worth $29 billion for more than 700 GE9X engines from airlines including Emirates, Lufthansa, Etihad Airways, Qatar Airways and Cathay Pacific.
The engine features 16 carbon-fibre fan blades at the front, which feeds air into an 11-stage high-pressure compressor with a 27:1 pressure ratio to boost efficiency. Four fuel tanks were installed for the tests for greater capacity.
The fuel nozzles were created through additive manufacturing and are composed of lightweight and ultra heat-resistant materials called ceramic matrix composites (CMCs), which can handle temperatures up to 1,316°C. This allowed the engineers to design the nozzles to have a complex internal structure.
CMC was also used in the combustor and turbine, enabling the engine to maintain high heat and with less fuel consumption and emissions.
GE Aviation has invested $10 million to prepare its Ohio test centre for the GE9X, including new materials for its testing stand that can withstand high temperatures and added reinforcements that will secure the engine.
The company also invested in a ‘bellmouth inlet duct,’ a white funnel attached to the front of the engine during testing, which measures 5.5m in diameter and 3.6m in length.
After five years of development, ground testing of the GE9X is now under way.
Bill Millhaem, general manager of the GE90/GE9X engine programmes at GE Aviation, said: “The ground testing will generate data on the full engine system and aerodynamic performance, mechanical verification, and aero thermal system validation.”