Hydrogen-powered propulsion aircraft: conceptual sizing and fleet level impact analysis
Creators: name:  W. LAMMEN 
name:   J. KOS 
name:   E. VAN DER SMAN 
name:   B. PEERLINGS 
Publisher: name: Proceedings of  the 9th European Conference for Aerospace Sciences. Lille, France, 27 June - 1 July, 2022
Year: 2022
Subjects: CLIMATE-NEUTRAL
AVIATION FUELS
ALTERNATIVE PROPULSION SYSTEMS

description: Climate neutrality by 2050 is a major objective of the European Green Deal to which aviation will have to contribute. Therefore, reducing greenhouse gas emissions is one of the main challenges for the development of future commercial aircraft. The development of hydrogen (H2) powered aircraft has recently become a topic of major interest, presenting the opportunity to eliminate CO2 emissions. In particular the on-board use of Liquid Hydrogen (LH2) is under investigation (e.g. [1]). In the frame of the EU Clean Sky 2 [2] project TRANSCEND [3] (Technology Review of Alternative and Novel Sources of Clean Energy with Next-generation Drivetrains), the impact of aircraft propulsion based on hydrogen was studied both at aircraft and fleet level. Three representative passenger aircraft with varying ICAO seat classes were selected as reference aircraft. For these reference aircraft weight and performance improvements were estimated, taking into account future entry-into-service (EIS). The future EIS years were assumed in line with the Clean Aviation Strategic Research and Innovation Agenda [4]. The three design cases are a regional turboprop configuration, seat class 20-50, 1000 km range based on ATR-42 aircraft, with EIS 2035; a narrow-body turbofan configuration, seat class 151-176, 2000 NM range based on Airbus A320neo aircraft, with EIS 2035; a wide-body turbofan configuration, seat class 211-300, 2000 NM range based on Boeing 787-8 aircraft, with EIS 2040. For these three design cases H2 propulsion aircraft configurations were conceptually sized and evaluated in terms of mission energy consumption and emissions. Propulsion based on H2 combustion by the gas turbine only, as well as parallel hybrid electric propulsion (HEP) variants were addressed in which the electric power is delivered by a fuel cell. The analyses were performed using the NLR in-house tool MASS (Mission, Aircraft and Systems Simulation for energy performance analysis [5]). Specific focus was given to the prediction of NOx emissions, H2O emissions and energy consumption. Parametric studies were applied to analyse the sensitivities of the predictions with respect to several assumptions such as the expected technology maturity. The initially applied models and assumptions were further refined taking into account recommendations from a dedicated workshop with experts in the field of aircraft hydrogen propulsion and its integration into aircraft, including storage. For the derived concept configurations various payload-range combinations have been evaluated in order to provide a table of corresponding performance results. Subsequently, these tables were used for evaluations at fleet level with a full-flight emissions model, developed by NLR in-house. For the fleet level evaluations future traffic scenarios from Clean Sky 2 were provided by the German Aerospace Centre (DLR), hereafter called the DLR Clean Sky 2 scenario. The fleet level evaluation results show regional as well as global impact of the introduction of modelled H2-powered aircraft. Additionally, the effect of wider introduction of H2-powered aircraft in intermediate size classes is estimated. The full paper will detail the conceptual sizing approach, the applied assumptions and the fleet level evaluation results. References [1] Airbus ZEROe, https://www.airbus.com/en/innovation/zero-emission/hydrogen/zeroe [2] Clean Sky 2 Joint Undertaking (JU), https://www.cleansky.eu/ [3] J. Kos P. Osseweijer T. Zill, European TRANSCEND for Novel Aircraft Propulsion and Alternative Fuels Roadmaps towards 2050, presented at the Aerospace Europe Conference, Bordeaux, 25-28 February 2020, NLR-TP-2020-171. [4] Strategic Research and Innovation Agenda, The proposed European partnership for Clean Aviation, Draft Version July 2020 [5] W.F. Lammen, W.J. Vankan, Energy Optimization of Single Aisle Aircraft with Hybrid Electric Propulsion, AIAA Scitech 2020 Forum, Orlando, FL, USA, January 6-10 2020. doi: 10.2514/6.2020-0505, NLR-TP-2020-114. Acknowledgements This research has been carried out in the TRANSCEND project, a Coordination and Support Action of Clean Sky 2s Technology Evaluator. This project has received funding from the Clean Sky 2 Joint Undertaking (JU) under grant agreement No 864089. The JU receives support from the European Unions Horizon 2020 research and innovation programme and the Clean Sky 2 JU members other than the Union. The German Aerospace Centre DLR is acknowledged for their provision of the DLR Clean Sky 2 scenario. Disclaimer The document reflects only the author\'s views and the JU is not responsible for any use that may be made of the information it contains.