During early phases of aircraft development, overall systems design is performed to estimate relevant system design parameters such as mass, power consumption, and compliance with architectural requirements (redundancy). The GeneSys software framework has been developed for parametric modeling of aircraft on-board systems for overall systems design. To this end, model-based architecture definition, topology generation (components positioning and connections routing), and system sizing are conducted. The topology generation is currently performed using design templates containing knowledge-based heuristics derived from systems topologies of existing aircraft. However, using such design templates limits their generic application to novel aircraft models because exceptions for geometric differences between these models need to be implemented. This especially applies to the topology generation of power supply systems (electric, hydraulic) due to their high number of interfaces to consumer systems. To overcome these limitations, an automated routing method is presented in this paper as a generic approach for topology generation. With this method, the system topology is generated based on a defined routing network, which comprises areas of the aircraft for allowed components positioning and connections routing. Using Dijkstra’s algorithm, the shortest path connections are found within the established routing network. Furthermore, boundary conditions for routing, for instance adding a cost function for power segregation, can be defined. An assessment of the automated routing method applied on the electric power supply system is performed using qualitative parameters such as the capability to adapt the routing network. Quantitative parameters like cable length and system mass are assessed as well.

The aircraft design process is a complex task that requires the collaboration of disciplinary experts from various fields. In practice, this complexity requires a large investment in setting up communication interfaces for the exchange of disciplinary data, and serious misinterpretations are not uncommon. To increase the efficiency and robustness of data exchange, a common language is essential. As such, the Common Parametric Aircraft Configuration Schema (CPACS) serves as a central data model, which currently includes detailed parametrizations of aircraft geometry and analysis results from traditional disciplines (e.g., aerodynamics, structure, etc.). However, with the recent interest in alternative propulsion and complex on-board system architectures, CPACS is proving to be too limited to meet the needs of the various disciplinary system experts. The particular challenge here is to enable different views on the same systems, i.e., a functional/logical as well as a geometric/physical representation, without violating the principle of unambiguous data. Therefore, this paper proposes an extension of CPACS which introduces an explicit system definition covering both representations. Its potential is demonstrated by two use cases from disciplinary experts in the field of on-board system design at the Hamburg University of Technology (TUHH), based on data provided by aircraft design experts. Through validation against the experts’ needs, the proposed system definition proves to bridge the gap between preliminary aircraft design and on-board system design, enabling a holistic, robust and efficient aircraft design process.

Integrating new technologies such as liquid hydrogen as an energy carrier is a key step toward climate-neutral and sustainable aviation. Current research mainly focuses on integrating cryogenic hydrogen tanks in the rear fuselage section. This paper presents an extended knowledge-based engineering (KBE) framework that enables the automated modelling and assessment of hydrogen tank integration concepts in preliminary aircraft design. The framework integrates several stages of the preliminary aircraft design process. Starting with openAD , a design synthesizer for determining the aircraft outer mold line and tank positions, followed by the Fuselage Geometry Assembler for generating structural, cabin, and cargo geometries as well as the Systems Architecting Assistant and GeneSys for system sizing and integration. Data exchange between these tools is realized through an XML -interface, and geometric consistency is ensured using the Open Cascade Technology library. Parametric data exchange with simulation environments is supported via CAD-exchange formats and the Common Parametric Aircraft Configuration Schema . The newly developed methods enhance an existing KBE-based fuselage design system with experimental tank mounts, crash structures, and hydrogen distribution systems. These additions enable a consistent and fully automated generation of structural and system models at the required fidelity level for future disciplinary analyses. The proposed method is demonstrated in a preliminary design study of two liquid-hydrogen-powered aircraft configurations, highlighting the improved automation, consistency, and integration capabilities of the extended KBE framework.

This paper presents an integrated assessment of liquid hydrogen as an aviation energy carrier, covering fuel production, aircraft performance, and fleet-level climate impacts. The results, based on the H2Avia research project, indicate substantial potential for reducing life-cycle global warming impacts compared to conventional kerosene. The analyses conducted for the interdisciplinary assessment are presented. The analysis shows that the use of liquid hydrogen eliminates CO₂ emissions during fuel burn, resulting in a significant reduction in global warming potential compared to conventional kerosene, despite remaining upstream emissions from production and transport. The aircraft application cases and the applied technologies assessment scenario are described. The modeled technologies essential for the hydrogen aircraft are discussed, and exemplary values are given. Integrated overall aircraft performance results are given and discussed. At the aircraft level, hydrogen-based aircraft require an 8–18% increase in design mission block energy compared to a 2040 kerosene baseline yet still achieve a reduction in effective global warming potential of 55–86% comparing a representative pair route between Europe and North America (6730 km). An overview of the fleet modeling approach and the applied scenarios is given. For a scenario with energy cost and climate impact as equally weighted minimization goals, the global fleet analysis yields a global warming potential reduction of 60% compared to the non-liquid hydrogen baseline scenario. Overall, the results suggest that liquid hydrogen-powered aircraft can deliver significant mission- and fleet-level reductions in global warming potential and thus represent a promising pathway for achieving long-term aviation climate targets.

Hydrogen-powered aircraft offer a promising pathway to reduce the aviation sector’s climate impact, with fuel cells providing high-efficiency power conversion at around 50%. However, producing considerable waste heat at around 80 $$^\circ $$ C. Since this heat is generated inside the aircraft, implementing an active thermal management system to dissipate it becomes a critical design consideration. In this paper, a holistic design methodology for the TMS to calculate its mass, power demand, and drag is presented. Exceeding previous work, the assessment includes the impact of this integration on the design of other on-board systems and the aircraft’s performance in terms of mission energy. Thereby explicitly covering "snowball effects" at the system level. Applied to the 70-passenger ESBEF-CP1 concept aircraft, the analysis shows that the TMS itself adds around 3850 kg system mass distributed over ten pods, 7 kN drag, and 700 kW peak fan power, resulting in a 29% increase in mission energy demand after only a single iteration of the other systems design. The findings highlight that relying solely on ambient air as a heat sink results in high drag and fan power demand, challenging aircraft feasibility.