Reducing aviation emissions

Improved integrated compressor duct technology enhances Rolls-Royce turbofan engine performance

Aviation carbon emissions are increasing. According to the ICCT, in 2018, passenger and cargo flights emitted 918 million tonnes of CO2 – a 32% rise since 2013.

Our research is supporting the design of new engines that are more fuel efficient and less polluting, helping the industry to become more sustainable and meet global environmental targets.

Image courtesy of Rolls-Royce plc

Our impact

Duct redesign improves engine efficiency

  • We helped Rolls-Royce to achieve a fuel burn saving of 0.25% in the Trent XWB engine.
  • This equates to an annual CO2 reduction of approximately 71 million kg across the current fleet of 379 Airbus A350.
  • This fuel efficiency represents cost savings of approximately £15 million a year.

Revolutionising engine design

  • Our new computational design methodologies have drastically reduced the development time and costs of the design process.
  • We have provided new, knowledge-based and patented solutions for three engine types - the Trent XWB, the Advance3 and the UltraFan.
  • These were validated on our unique test facility, reducing the need for costly full-scale engine testing.

The research

Our work has helped Rolls-Royce to make a paradigm shift to more efficient geared turbofan architectures with ultra-high bypass ratios and very-high pressure ratios.

The annular s-shaped transition ducts connecting the low- and high-pressure compressors in aero engines have conflicting aerodynamic and structural requirements – making their redesign a challenge.

Working with Rolls-Royce and the University of Cambridge (2004-11), we developed an improved understanding of duct aerodynamics as well as new numerical methodologies and innovate designs. Our bespoke test facility enabled this work at a fraction of the cost and time of conventional engine tests – achieving significant design improvements.

The next stage of our work (2011-15) focused on further improving the aerodynamic integration of neighbouring components. By integrating support struts into the compressor outlet vanes – in a now patented design we realised further efficiencies.

We then explored the potential savings of redesigning components downstream of the fan feeding the engine core (2016-19). Employing a combination of computational and experimental methods, we developed new integrated designs.

Meanwhile, in collaboration with GKN Aerospace (2018-20), we investigated the impact of a bleed at the exit of the compressor immediately upstream of the transition duct that allows more efficient engine operation. We identified failure mechanisms and bleed limits, providing clear boundaries to the design space.

Together, these redesigns have achieved significant fuel cost and emission reductions, supporting the industry’s progress toward sustainability.

The partnership between Rolls-Royce and Loughborough has roots as far back as the 1970s and offers a unique opportunity to develop and translate technologies in jet engines.

Dr John Bolger Rolls-Royce Engineering Fellow – Aerodynamics

Research funders

  • EU – Framework Programmes 6 and 7, Horizon 2020, and Clean Sky
  • UK – ATI, Innovate UK, and EPSRC

Development partners

  • GKN Aerospace
  • Rolls-Royce
  • University of Cambridge

Meet the experts

Photograph of Duncan Walker

Dr Duncan Walker

Reader in Applied Aerodynamics

Photograph of Jon Carrotte

Professor Jon Carrotte

Professor of Aerothermal Technology