CFM International pursues open fan engine for cleaner aviation
The RISE technology demonstration program aims to develop a new engine architecture that reduces fuel consumption by at least 20%.
CFM International, a collaboration between GE Aerospace and Safran Aircraft Engines, is ramping up efforts on its RISE (Revolutionary Innovation for Sustainable Engines) technology demonstration program. This initiative aims to tackle the environmental issues facing the aviation sector.
The initiative, which aims to develop a new engine architecture, promises to reduce fuel consumption by at least 20% compared to current engines while tackling critical issues such as noise pollution and contrail formation.
To coincide with the Farnborough Air Show, senior CFM executives shared insights into the program's progress with Sustainability in the Air.
What makes RISE noteworthy is that it comes from a major supplier of commercial aircraft engines — CFM International was founded in 1974. A 50/50 joint venture between GE Aerospace and Safran Aircraft Engines, CFM International is particularly known in the industry for its LEAP family of engines.
Pierre Cottenceau, Executive Vice President of Engineering and Research and Technology at Safran Aircraft Engines, expressed confidence in the project’s achievements: "We have made significant progress in our testing plan, which confirms the benefits of the open fan propulsive system for the next generation of single-aisle aircraft."
Central to the RISE program is the open fan engine design, a departure from conventional aircraft propulsion systems. New technologies and strategic partnerships have bolstered the initiative.
Addressing noise pollution and contrail formation
Mohamed Ali, Senior Vice President of Engineering at GE Aerospace, highlighted the program's use of advanced computing resources.
"We were the first business in the world in 2023 to gain access to Frontier, the world's fastest and largest supercomputer," Ali noted. "This allows us to practically model at the molecular level, enabling us to design and understand noise and fuel performance in massive detail."
The program's focus extends beyond fuel efficiency. Recognising that sustainability encompasses more than just emissions reduction, the RISE team is addressing noise pollution, a longstanding concern for communities near airports.
Ali expressed confidence in their progress: "We are quite comfortable from the test results we have done, both in wind tunnel and supercomputing simulations, that we'll achieve lower noise levels than today's most modern aircraft. We've shown that we can meet or beat all future noise requirements."
Another environmental concern being tackled by the RISE program is the formation of contrails, which contribute significantly to aviation's climate impact.
"We are developing insights about when contrails form and the basic physics and chemistry of how they develop," Ali explained. "These insights are enabling us to advance and develop technologies to reduce contrail formation."
Hybrid-electric dreams and 100% SAF compatibility
The program is also exploring hybrid-electric propulsion, with both GE Aerospace and Safran advancing these technologies. GE is currently modifying a Passport 20 engine to incorporate a motor generator. Ali described this innovation as "like a hybrid car, but with no batteries required. We'll be able to share energy between the two engine spools, managing different phases of flight in a more efficient way."
To date, the RISE program has completed over 250 individual tests, including more than 200 hours of wind tunnel testing using a 1:5 scale model of an open fan. Full-size open fan blades and outlet guide vanes have been manufactured and tested, and durability tests on high-pressure turbine airfoils are underway.
The program is designed to be compatible with 100% sustainable aviation fuel, which can reduce fuel lifecycle emissions by up to 80%, depending on the feedstocks used. Cottenceau emphasised this point:
"This new architecture will be 100% compatible with sustainable aviation fuel, which will enable a drastic reduction in CO2 emission beyond the reduction in fuel consumption."
Gael Meheust, President and CEO of CFM International, underscored the program's importance in a media announcement released to coincide with the Farnborough International Airshow: "As CFM celebrates its 50th anniversary, we are acting on our clear ambition to make air transport more sustainable. With the RISE program, CFM will, once again, change the way that people fly."
As the aviation industry grapples with its environmental impact, the RISE program represents a comprehensive approach to addressing multiple sustainability challenges. Over 2,000 engineers globally support the development of RISE program technologies.