The EU VITAL programme promoted the research and development of new concepts for environment-friendly aircraft engines. In one work package, the concept of a counter-rotating engine fan was investigated. Participants in this project were international research institutes and companies such as SNECMA, ONERA and VibraTec (France), CIAM (Russia), COMOTI (Romania), NLR (Netherlands) and various DLR institutes in Germany (Institute of Propulsion Technology, Institute of Structures and Design, Institute of Aeroelasticity).
Multiple counter-rotating fan configurations were investigated in this project, in collaboration with international partners. One version of a lightweight, counter-rotating fan was developed entirely at DLR. Using a comparatively small number of blades, a high mass flow was achieved with a high level of efficiency. At the same time, the mechanical property specifications guarantee a standard lifetime for the fan in real applications.
The Institutes of Propulsion Technology, Structures and Design and Aeroelasticity were responsible for the development within the DLR. The Institute of Structures and Design led the structural design element of the project. The multidisciplinary design process involved aerodynamic and structural mechanical specifications. The optimisation process, already demonstrated at the Institute of Aerodynamics and Flow Technology, was also used for the mechanical construction. This joint optimisation led to an ideal interdisciplinary result that represents a compromise between the, at time conflicting, optimisation objectives of the individual disciplines.
Upon completion of the design work, the capabilities of the concept were tested on a test rig at CIAM in Russia, once the two compressor rotors were manufactured in Germany under the guidance of DLR. The aerodynamic, aeroelastic, acoustic and mechanical stability simulation results were successfully validated using the test results. Overall, the project is an example of DLR’s demonstrable system expertise.