Future engine architectures: innovation under the hood!
In the aim of reducing fuel consumption in the next generation of engines, Safran is studying architectures with a very high dilution ratio, known as UHBR type engines*, characterized by a wider fan diameter. Within the framework of the European project NIPSE**, several Group companies have focused on incorporating these innovative propulsion systems, with promising results.
5 to 10%: is the target efficiency gain in terms of fuel consumption for UHBR engine architectures. It is an appealing prospect, but one which involves overcoming a number of design and integration challenges. Starting with increasing the fan diameter, which minimizes the space available for equipment typically housed between the engine and the nacelle. “That which we refer to as the engine housing includes more than forty pieces of equipment, such as electrical harnesses and boxes or even thrust reverser actuators, to name just a few...” explains Vincent Peyron, nacelle architect at Safran Nacelles.
Automating certain integration tasks
How can we optimize the integration of all this equipment? The NIPSE project partners have been exploring this question for three years. Under the technical coordination of Safran Nacelles, they have examined three major areas for improvement, proposing groundbreaking solutions for each one. First area: reducing development time. “This is a global trend in the aeronautics industry,” Vincent Peyron reminds us, “but it is especially important for complex architectures like UHBR engines that require the design of smaller equipment that is better functioning and more resistant to extreme temperatures.” Well aware of these challenges, the NIPSE project partners have identified a tool for automating the routing of harnesses and piping in a matter of a few minutes. Result: a time savings of 40 %.
Smaller, lighter, more accessible
The second objective was to reduce the volume and mass of equipment. Success once again: a 10% gain was noted, thanks mainly to additive manufacturing. Safran Electrical & Power, which specializes in electrical harnesses, suggesting using flat wires and a wireless connection for certain electrical signals. The third and final challenge faced by the NIPSE project: to maintain the same access time to systems and equipment for engine maintenance, despite their new arrangement under the nacelle. “Today,” explains Vincent Peyron, “the engine housing is primarily located around the fan. Tomorrow, it will be shifted further back, under the thrust reversers. In order to gain access, you must also open these other elements of the nacelle, which could prolong maintenance time.” The solution? An innovative automated opening tool, designed according to Safran Nacelles’ specifications. This will make it possible to open the covers more quickly and safely. “More generally speaking,” continues Vincent Peyron, “the joint expertise of Safran Aircraft Engines and Safran Nacelles has been especially useful for optimizing engine and nacelle integration. Indeed, one of the key strengths of the project has been the joining together of all concerned players in the face of challenges relating to UHBR.”
What the future holds, however, remains unknown. “The solutions uncovered in the NIPSE study will be subject to further development as part of R&D projects conducted by the various partners,” estimates Vincent Peyron. Many of these topics are already being explored at Safran.
* Ultra-High Bypass Ratio.
** Novel Integration of Powerplant System Equipment. Project financed by the European Commission as part of the Horizon 2020 research and innovation program. Project partners: Safran Nacelles, Safran Aircraft Engines, Safran Electrical & Power, Netherlands Aerospace Center (NLR), Thermocoax, Meggitt, BAE Systems, Compañía Española de Sistemas Aeronáuticos (CESA), Archimedes Center for Innovation and Creation et ARTTIC International Management Services.
Dilution ration: a growing trend!
In a by-pass turbofan type jet engine, the dilution ratio measures the relation between the flow of cool flow (air circulating between the turbo engine and the external structure of the nacelle) and the hot flow (air entering the turbo engine before being burned with the fuel and released).The higher this ratio, the lower the fuel consumption for a given thrust. Over the last few decades, the dilution ratio of engines has continuous increased, from 6:1* in CFM56 engines to 11:1 in LEAP engines. UHBR architectures aim to reach a dilution ratio of over 15:1.
* A dilution ratio of 6:1 indicates, for example, than for every 6 volumes of air circulating in the turbo engine, 1 volume of air enters.
Visit the NIPSE project website
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- © Cyril Abad / CAPA Pictures / Safran