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Contra-Rotating Open Rotor (CROR) Propeller barrels

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Cleaner engines for greener aviation

An EU-funded project successfully developed critical aviation engine components for innovative propulsion systems destined for aircraft of the future.

Transport and Mobility

Whether operators or manufacturers, the entire aviation industry shares the same key goals: to drive down costs by reducing fuel consumption, mitigating harmful emissions and decreasing noise. One of the most amazing new engine architectures promising to make aircraft more eco-friendly and less costly is the contra-rotating open rotor (CROR), being developed as a technology demonstrator in the European research programme Clean Sky. Open rotor engine architectures allow a high increase in the bypass ratio compared with current engines in use. The bypass ratio of an open rotor can reach 50:1 compared to that of current engines of 14:1. Featuring two sets of uncased blades that rotate in opposite directions, they can cut fuel consumption by 30 % compared with current aircraft. The GREENBARRELS (Contra-rotating open rotor (CROR) propeller barrels) project supported the European Clean Sky initiative by designing, manufacturing and delivering several critical components to be integrated into the CROR engine being developed under the EU initiative. Components developed by the project team are the so-called transition and aero ducts – also called barrels because of their shape. Functions of these components include channelling the flow of the stream of the main hot gases to the exhaust, channelling the secondary airstream and channelling cooling air for the lubrication oil. Particular focus was placed on finding the right design to sustain the functional and failure loads. The development included analysis of load cases, dynamic analysis, fatigue analysis, assembly analysis, manufacturing analysis and analysis of the right quality plan for the parts. GREENBARRELS work forms part of Clean Sky’s Sustainable and Green Engine (SAGE) integrated technology demonstrator. This is developing engine technologies for low-noise and lightweight low-pressure systems, high efficiency, low nitrogen oxides emissions, and low-weight cores and novel configurations such as open rotors and intercoolers. These efforts are aimed at giving the aviation industry more efficient and cleaner aircraft in the future.


Aviation, aircraft, fuel consumption, contra-rotating open rotor, GREENBARRELS, aero ducts

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