Gaining a better understanding of the Climate Impact of Future Aircraft Engines

To date, contrails have been studied primarily through flight tests. However, for many future propulsion concepts, no flight-ready engines exist yet, making such measurements impossible. At the same time, data collected under controlled and reproducible conditions are needed to better understand the underlying physical processes and validate existing models.

KlimaRAT (Demonstration of Contrail Formation and Design Capabilities of Revolutionary Turbofan Technologies for Reducing Climate Impact) lays the scientific foundation for this. In this project, contrails are generated and studied for the first time under realistic atmospheric conditions in the altitude test facility at the University of Stuttgart. The goal is to systematically identify the key factors influencing their formation and to use the results for the development of climate-friendly aircraft propulsion systems.

The DLR Institute of Atmospheric Physics is investigating the influence of emissions, such as aerosol concentration, water content, and temperature of the exhaust plume, as well as atmospheric conditions, on contrail formation. To address these questions, contrails are generated under defined conditions at the University of Stuttgart’s high-altitude test facility, measured with instruments used in flight, and compared with their high-resolution models.

At the same time, the DLR Institute of Combustion Technology is testing measures to reduce gaseous and particulate emissions. Supplementary combustion chamber investigations at the institute provide information on engine emissions and boundary conditions for the experiments on the high-altitude test rig. The results are then incorporated into simulation models that can be used to assess the climate impact of future aircraft fleets.

Another focus of the project is the rapid introduction of new propulsion technologies. The DLR Institute of Maintenance, Repair and Overhaul, working closely with the collaborators, is investigating how innovative engine concepts affect maintenance and repair. Simulation models are used to analyze and optimize future maintenance processes. This allows potential impacts on maintenance costs and time to be identified early on and taken into account during the development of new technologies.

The work in the KlimaRAT project helps to assess the climate impact of future aircraft engines at an early stage while simultaneously accelerating their development and subsequent introduction into flight operations.Ideally, this will allow for the identification of operating points for new engines that reduce the contrail effect.