New concept Generation Y set to become template for all of manufacturer's future large commercial turbofans

General Electric has revealed plans to develop an advanced technology "intelligent" engine family, which could form the basis for all future large GE commercial turbofans.

The engine, dubbed Generation Y, is being designed as a long-term stablemate for GE's recently begun GEN X Sonic Cruiser engine study, and the three-year CFM International Tech56 technology development programme based on the CFM56.

Generation Y, available from 2015, is also seen as a follow-on to NASA's Ultra-Efficient Engine Technology (UEET) programme, with a focus on practical development into a service-ready propulsion system. The outline Generation Y targets are "not far from UEET goals, and include an 85% reduction in NOx [nitrous oxide] relative to International Civil Aviation Organisation 96 rules, and a cut in carbon dioxide emissions and fuel flow by 20% compared to the GE90", says GE advanced engine programmes general manager Mike Benzakein.

The UEET goals, by comparison, include 70% lower NOx and fuel savings of up to 15%.

According to Benzakein, NASA is intending to continue with its support. He says: "We've set some pretty lofty goals," adding that the effort will build on the UEET, which is "due to be completed by 2005-06, but Generation Y needs more longevity". The programme is starting on a component basis, Benzakein says.

"It works towards a platform approach, looking at combustors, fluidics, composites and nanotechnology areas. There will be lots of intelligent sensors and controls, and it will be an intelligent engine with on-condition maintenance."

Noise goals include a 33EPNdB cumulative reduction below Stage 3 limits, to be achieved with a bypass ratio of between eight and 10, rather than the 15 to 20 levels of GE90-style designs.

"We need to keep bypass ratio under control to make sure it's a balanced product," Benzakein says, adding the focus will be on core development for efficiency, and GE is working on a six-stage design with a high-pressure (HP) ratio of 20:1. The core configuration will include single and dual annular combustor stages.

GEN X work for Boeing's Sonic Cruiser is "taking on different shapes, depending on what sort of aircraft we are looking at", says Benzakein. GE's study is based on an 80% scale version of an evolved nine-stage HP compressor design developed from the GE90-115B programme.

Source: Flight International