Advancements in Next-Generation Aircraft Engine Technologies: Insights from Boeing and GE Aerospace
Over the past year, prominent figures in the aviation industry, such as Boeing and GE Aerospace, have outlined ambitious technology development roadmaps. These plans mark some of the most extensive technological advancements in these companies’ storied histories, spanning over a century. The overarching goal is to usher in a new era of next-generation commercial aircraft engines, with the potential to enter service around the mid-2030s. Numerous ground and flight tests scheduled for this decade will focus on pioneering technologies that could reshape the aviation landscape.
Among the cutting-edge engine architectures under scrutiny are open fan designs, hybrid electric propulsion systems, and compact engine core configurations. These innovations will undergo rigorous testing in the coming years and are poised to be pivotal programs to monitor throughout 2023 and beyond.
In line with the aviation industry’s long-term climate objective of achieving net-zero carbon emissions by 2050 for commercial flights, revolutionary technologies and alternative fuels play critical roles. Notably, GE has outlined its top innovations and industry-leading initiatives that contribute to the journey toward a net-zero future.
Open Fan Engines and the CFM RISE Program:
Open fan engine designs have been enhanced for simplicity and weight reduction through innovations like single-stage rotating carbon fibre composite fan blades and stationary outlet guide vanes. This evolution reflects the industry’s ongoing pursuit of enhanced propulsive efficiency, which has led to the development of open fan concepts. This advanced open fan architecture is engineered to operate at the same speeds as current single-aisle aircraft (up to Mach 0.8 or 80% of the speed of sound) while complying with anticipated future noise regulations.
The open fan design is a key component of CFM International’s research agenda, a joint venture between GE and Safran Aircraft Engines, carried out through the CFM RISE Program. The program’s objectives encompass reducing fuel consumption and CO2 emissions by over 20% compared to today’s most efficient engines, while also ensuring compatibility with alternative energy sources like Sustainable Aviation Fuels (SAF) and hydrogen, thus amplifying sustainability benefits. The program strives to achieve groundbreaking performance levels while maintaining CFM’s unmatched standards for reliability, asset utilisation, and overall cost of ownership.
Hybrid Electric Propulsion:
Hybrid electric propulsion, which combines gas-powered turbines with electric motors, is a pivotal technology being matured to meet industry targets for reducing carbon emissions from air travel. With the RISE Program, CFM is on track to become the first company to introduce hybrid electric systems in the single-aisle segment. GE and Safran’s unique position in the industry stems from their legacy of expertise in electrical engineering, manufacturing, electrical power distribution, generation, and advanced materials research.
Smaller Engine Cores for Greater Efficiency:
Innovations are underway to test and refine new jet engine core designs, including advancements in compressors, combustors, and high-pressure turbine technologies. These innovations aim to enhance thermal efficiency, a crucial factor in engine performance.
Pioneering Sustainable Aviation Fuel (SAF):
United Airlines marked a significant milestone by operating the first passenger flight utilising 100% SAF in one of the CFM LEAP-1B engines on December 1. This historic flight not only carried over 100 passengers from Chicago to Washington, D.C., but it also represented progress in pushing SAF beyond the current blending limit of 50%. Current SAF approved for use is a blend of petroleum-based Jet A or Jet A-1 fuel and SAF components, with a maximum blend limit of 50%. CFM has been extensively testing SAF since 2006, and the industry is actively exploring the certification of 100% renewable fuels for existing aircraft, which would accelerate the reduction of CO2 emissions when supported by the global availability of synthetic fuels.
Pioneering Hydrogen Combustion:
Building on experience with hydrogen fuels in land-based gas power turbines, efforts are underway to ground, and flight test a direct combustion engine fuelled by hydrogen. The goal is to prepare for the introduction of zero-emission aircraft by 2035.
Boeing is committed to reducing emissions through four strategic pathways.
Boeing’s Strategic Approaches to Emission Reduction: fleet renewal, renewable energy, advanced technologies, and operational efficiency.
Fleet Renewal: New generations of aircrafts offer significant efficiency gains, reducing fuel consumption and emissions. For example, the 737 MAX, powered by CFM International LEAP-1B engines, incorporates optimised aerodynamics, resulting in a 20% reduction in fuel use and emissions compared to its predecessors. The 787 Dreamliner offers 25% lower fuel consumption and emissions, while the forthcoming 777X promises 10% lower fuel use and emissions, as well as lower operating costs.
Renewable Energy: Boeing is actively working toward enabling the use of 100% SAF (sustainable aviation fuel) as soon as possible.
Advanced Technologies: Battery technology advancements are expected to enable electric aircraft, especially for urban air mobility. Boeing is poised to incorporate electrification when it optimises energy management and enhances overall aircraft performance and efficiency. The 787 Dreamliner is an example of Boeing’s more-electric architecture, generating 1.45 megawatts of electrical power, significantly surpassing the power output of current aircraft like the 767.
Operational Efficiency: Boeing is collaborating with air traffic controllers worldwide to optimise aircraft flight paths from take-off to landing. Initiatives such as multi-regional Trajectory Based Operations (MR TBO) are enhancing operational efficiency and sustainability.
In summary, the aviation industry is making significant strides in developing next-generation aircraft engine technologies, fuelled by a commitment to reducing carbon emissions and enhancing sustainability. These advancements encompass open fan engines, hybrid electric propulsion, improved engine cores, the adoption of SAF, and exploration of hydrogen combustion. Additionally, Boeing’s strategic approaches to fleet renewal, renewable energy, advanced technologies, and operational efficiency further contribute to the industry’s efforts to achieve its environmental goals.