Periodic Reporting for period 2 - SIENA (Scalability Investigation of hybrid Electric concepts for Next-generation Aircraft)
Reporting period: 2022-02-01 to 2023-07-31
The aviation industry has committed to a set of ambitious goals to reduce fuel burn, emissions and noise by 2050, including a commitment to flying Net Zero by 2050. To help achieve these goals, new radical aircraft architectures have to be designed in a way that are not only technically feasible but also operationally and economically viable. Alternative propulsion technologies have been increasingly investigated as a way to provide the necessary reduction in emissions. The complete electrification of the propulsion system is one of the options to achieve these goals, but while a fully electric vehicle has been realized for general aviation aircraft, fully electric aircraft of larger sizes are not feasible in a short time period. This is due to a number of technology challenges such as energy density of batteries, the challenge in achieving higher power density motors and converters and the complexity of their thermal management. Therefore, combinations of Hybrid-Electric Propulsion (HEP) technologies with novel technologies, such as complex aero-propulsive couplings, novel thermal management technologies and non-drop-in fuels (such as hydrogen) are considered as options to replace part of the A/C propulsive capacity. The multitude of promising technologies, and the way they can be combined and integrated in A/C, results in a very large number of design options.
SIENA is focused on the development of a systematic methodology that enables scalable-by-design architectures by studying the feasibility of integrating different technologies in novel aircraft architectures in such a way that they can be scaled-up from smaller to larger passenger aircraft. SIENA also delivers a comprehensive study of different technology choices in novel aircraft architectures with respect to their performance, operations and economic impact and their capability to scale-up across different categories.
SIENA is focused on the development of a systematic methodology that enables scalable-by-design architectures by studying the feasibility of integrating different technologies in novel aircraft architectures in such a way that they can be scaled-up from smaller to larger passenger aircraft. SIENA also delivers a comprehensive study of different technology choices in novel aircraft architectures with respect to their performance, operations and economic impact and their capability to scale-up across different categories.
One of the main features developed in the project is the combination of the conceptual aircraft design software from the Politecnico di Milano with the design space exploration and system design capabilities at Collins Aerospace. Five aircraft categories ranging from general aviation to long-range commercial transports were evaluated for six different baseline system architectures and different future technology scenarios. An economic and operational analysis evaluated the novel aircraft on different missions, performed a sizing of refueling facilities, and created a business case to assess the economic viability. A regulatory analysis reviewed the current certification regulations and identified gaps to be closed for novel propulsion system architectures.
Based on the assumed technology advancements, the results suggest that parallel hybrid systems (battery and fuel cell-powered) are scalable across the different aircraft category due to the various options of hybridization. In general, the degree of hybridization decreases with range and aircraft size due to the rather low power and energy densities of the electric components.
The studies also showed that hydrogen-based systems (hydrogen combustion and fuel-cell-electric) have the highest potential in terms of mission energy savings with the assumed technology advancements. In this context, 2030 technologies would suffice for smaller aircraft up to regional turboprop, while for larger aircraft, 2050 technologies would be required. On the other hand, the hydrogen-based architectures come with large efforts to close the regulatory gaps and uncertain economic viability in terms of hydrogen production, storage, and logistics.
The results of the project were published via conference presentations and papers such as the European Aeronautics Science Network (EASN) conferences 2021, 2022, and 2023, the World Congress of Structural and Multidisciplinary Optimisation (WCSMO) 2023, and the Aerospace Europe Conference ( 10th EUCASS - 9th CEAS) 2023.
Based on the assumed technology advancements, the results suggest that parallel hybrid systems (battery and fuel cell-powered) are scalable across the different aircraft category due to the various options of hybridization. In general, the degree of hybridization decreases with range and aircraft size due to the rather low power and energy densities of the electric components.
The studies also showed that hydrogen-based systems (hydrogen combustion and fuel-cell-electric) have the highest potential in terms of mission energy savings with the assumed technology advancements. In this context, 2030 technologies would suffice for smaller aircraft up to regional turboprop, while for larger aircraft, 2050 technologies would be required. On the other hand, the hydrogen-based architectures come with large efforts to close the regulatory gaps and uncertain economic viability in terms of hydrogen production, storage, and logistics.
The results of the project were published via conference presentations and papers such as the European Aeronautics Science Network (EASN) conferences 2021, 2022, and 2023, the World Congress of Structural and Multidisciplinary Optimisation (WCSMO) 2023, and the Aerospace Europe Conference ( 10th EUCASS - 9th CEAS) 2023.
The advances beyond the state of the art brought by SIENA rely on three levels: the development of a methodology that brings the different design aspects and constraints across vehicle categories together in a scalable-by-design fashion, advancement of methods and tools, modelling and evaluation of technical, operational and economic aspects, and the identification of regulatory constraints.
The SIENA concept is built around the notion of scalable-by-design: the aim is to include the definition of scalability into the design process for HEP concepts across categories, offering design solutions that are scalable-by-design rather than optimal/optimized only for the current vehicle size. This is a potential innovation which could be replicable for feasibility studies across industries and within the aviation sector considering other aspects of radical architecture designs. SIENA will also help identify the most promising scalable technologies across vehicle classes, enabling a more competitive market and lower costs for manufactures and end-users, and allowing for the accelerated adoption of new technologies
Finally, SIENA will also analyse aircraft operations across categories to identify new operational patterns due to the new technologies and enhance the mobility of European citizens.
The SIENA concept is built around the notion of scalable-by-design: the aim is to include the definition of scalability into the design process for HEP concepts across categories, offering design solutions that are scalable-by-design rather than optimal/optimized only for the current vehicle size. This is a potential innovation which could be replicable for feasibility studies across industries and within the aviation sector considering other aspects of radical architecture designs. SIENA will also help identify the most promising scalable technologies across vehicle classes, enabling a more competitive market and lower costs for manufactures and end-users, and allowing for the accelerated adoption of new technologies
Finally, SIENA will also analyse aircraft operations across categories to identify new operational patterns due to the new technologies and enhance the mobility of European citizens.