GEnx

Avio is responsible for the design, development, production and MRO.

The accessory drive train includes the:

• inlet gearboxes (IGB) and transmission of motion (TGB or transfer gearbox), which transfer torque from the high-pressure shaft (HP spool) of the engine to the accessory drive train. Both gearboxes are located on the front frame of the engine (technically called Fan Hub Frame)
• vertical transmission shaft and horizontal shaft, which connect respectively the IGB to the TGB, and the TGB to the accessory drive train
• accessory drive train, core mounted (mounted axially next to the high-pressure compressor), which drives the accessories of the engine and aircraft

The accessory drive train successfully passed all certification tests (bench test and engine) and dynamics tests to confirm the robustness of the kinematic chain in case of limited dynamic phenomena, though confirming the high competences achieved by Avio in the field of dynamic modelling of modern aircraft transmissions. 

Avio responsibility includes the design, development, production and MRO of the static components of the low-pressure turbine.

Avio responsibility has effectively been extended to all the static structures on the aerodynamic turbine duct (flow path). In particular:

• seven stator blade stages (LPT nozzles), the first of which is located on the Turbine Centre Frame, and the subsequent 6 stages on the LP turbine module. These stages make use of advanced materials to meet high entry temperatures and reduce the operating cost of the turbine through a high resistance to the phenomena of fatigue, wear and hot flow (so-called creep)
• three cast shroud stages, to ensure correct radial clearances (and ultimately performance) and protect the turbine casing from the high temperature jet
• four plate shroud stages, to ensure correct radial gaps (and ultimately performance) and protect the turbine casing from the high temperature jet
• turbine casing, produced through individually forged Waspaloy alloy, and extremely challenging in terms of project and construction manufacturing

The aerodynamic design of the turbine made extensive use of CFD 3D modelling techniques that brought about a reduction in the number of parts and weight, and the attainment of the performance necessary to bring the GEnx to levels of specific fuel consumption improved by 15% with respect to the previous generation of engines of the same thrust class. 

Avio’s contribution in terms of design and system integration was also extended, as well as fluid dynamics analysis, and the analysis of clearances and flutter phenomena. The LPT successfully passed all certification tests and established a reference point for reduced development times for all next-generation aeronautical turbines.

Under the 2B programme, Avio designed and developed equivalent components with the equivalent level of responsibility. 

Avio developed and is responsible for a significant number of components of the engine lubrication system, such as the

• feed and recovery oil pump (not shown)
• oil tank and relevant attachments and accessories: oil level and temperature sensor (OLTS), filler cap/dipstick and oil strainer
• engine health monitoring system (oil debris monitoring system)

The oil system is common to the GEnx 1B and 2B engines and there are no differences between the two engine models.