THE SUSTAINABILITY BENEFITS OF GEARED TURBOFAN ENGINES

In a traditional dual-spool turbofan, the low-pressure shaft connects the fan, low-pressure (LP) compressor, and the LP turbine. A second high-pressure (HP) shaft connects the HP compressor and the HP turbine. The two shafts run concentrically at different speeds, increasing the engine's overall efficiency. The LP system of a typical narrowbody engine runs at 3,000 rpm, while the HP shaft runs at approximately 15,000 rpm.

In a geared turbofan (GTF) design, a reduction gearbox is installed between the fan and the LP shaft to allow the two to spin at different (optimal) rotational speeds. The gearbox maintains the fan tip speeds below supersonic levels while keeping the overall fuel efficiency at an acceptable level. The management of fan speed enables fewer LP compressor and turbine stages, which in turn reduces engine weight.

While some of the weight is offset by the addition of the gearbox, optimal speeds lead to better fuel efficiency and sustainability. Within the LP system, the tip speed of the fan increases relative to the speed of the turbine blades. Moreover, GTF engines use minimal air for expansion which makes them fuel efficient.

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Sustainability benefits

The Pratt & Whitney PW1000G is a high-bypass GTF engine developed to power a range of narrowbody aircraft. The GTF architecture has enabled up to 16-20% better fuel efficiency for single-aisle aircraft while significantly reducing carbon emissions. The GTF Advantage engine for A320neo family aircraft extends the economic and environmental benefits of the existing GTF engine. According to the President of Commercial Engines at Pratt & Whitney, Carroll Lane,

The GTF Advantage programme is an 11 engines programme and P&W is about a 1000 hours into the programme, with over one year of ground and flight testing complete.

The GTF Advantage configuration includes technology enhancements throughout the engine core. The engine delivers higher thrust, both at sea level and at high-altitude airports. Available for the A320neo family aircraft starting in January 2024, the GTF Advantage will reduce fuel consumption by an additional 1%, reducing the carbon footprint even further. The engine will enable 4% additional takeoff thrust at sea level and up to 8% more at high-altitude airports.

With up to 34,000 pounds of takeoff thrust, the Advantage configuration makes GTF the most powerful engine for the A320neo family. Operators can achieve a higher payload and range thanks to the increased thrust.

The new configuration will be interchangeable and intermixable with the base GTF models. Having the same aircraft interface, the newer model provides greater flexibility for the operators. Moreover, aircraft can successfully operate one of each configuration, maximizing efficiency irrespective of the engine pairing. Carroll Lane commented,

GTF engines met or exceeded fuel, emissions and noise commitments from day one and have since achieved a strong record of dependability and low operating cost. GTF Advantage provides even more value to our customers, both in revenue potential and environmental impact, with lower fuel burn and new route opportunities.

The GTF Advantage engine will be compatible with 100% sustainable aviation fuel (SAF) at its entry into service in 2024.

What are your thoughts on the sustainability perspectives of GTF engines? Tell us in the comments section.

2023-06-11T00:30:56Z dg43tfdfdgfd