Cluster of Excellence: Sustainable and Energy-Efficient Aviation - Research for sustainable advanced eFuels

The Cluster of Excellence SE²A is an interdisciplinary research project with the aim of exploring technologies for the sustainable and environmentally compatible development of air transport. In the cluster, scientists from the fields of aeronautics, electrical engineering, energy, chemistry and design are working on the reduction of emissions, the reduction of noise pollution, the recyclability of air transport systems and the further development of air traffic management. In addition to the TU Braunschweig, the German Aerospace Center (DLR), the Leibniz University of Hannover (LUH), the Braunschweig University of Fine Arts (HBK) and the Physikalisch-Technische Bundesanstalt (PTB) are involved in SE²A.

In subproject C3.3 from ITV Hannover in collaboration with PTB (Prof. Ravi Fernandes), the combustion properties of advanced liquid electro-fuels (eFuels) are investigated and tested for their suitability for combustion in lean premixed prevaporized (LPP) combustors. Such LPP combustion of eFuels in aero engines would enable ultra-clean aviation, as it would be operated without any soot particles and almost without NOx emissions. In principle, eFuels include fuels produced with sustainable, renewable electricity (e.g., from wind and solar) and carbon from biomass or atmospheric CO2, which allows them to be considered CO2-neutral.

The focus of the research is to find the eFuel with suitable properties such as sufficiently long ignition delay times for the mixing section of the LPP combustor and with appropriate flame stability. Currently, we are concentrating here on oxygenated hydrocarbon compounds such as alcohols and furans, being synthesized electrochemically.

For experiments, a flexible mixing and burner arrangement is set up at ITV to study the processes of pre-evaporation, pre-mixing, pre-ignition and flame flashback for very different fuels with quantitative variation of fuel-air mixing ratio and preheat temperature. In addition, chemical kinetic mechanisms are developed and validated. The combustion and flame stabilization properties of various liquid eFuels will be investigated, which will be analyzed in collaboration with other groups in the Cluster of Excellence such that both synthetic production capabilities and combustion properties can be related and structure-property-relationships can be established. This is an important step towards sustainable and environmentally clean aviation.