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Global-Warming-Optimized Aircraft Design

Periodic Reporting for period 1 - GLOWOPT (Global-Warming-Optimized Aircraft Design)

Reporting period: 2019-09-01 to 2021-02-28

GLOWOPT addresses the Thematic Topic “Aircraft Design Optimization providing optimum performance towards limiting aviation’s contribution towards Global Warming. The project is set to directly contribute to this challenge by developing innovative Climate Functions for aircraft design (CFAD) that allow for a minimization of the climate impact of next-generation aircraft within the Multi-disciplinary Optimization (MDO) process.
The high-level objective of the proposed GLOWOPT project is the development and validation of CFAD with respect to minimizing global warming and their application to the MDO of next-generation aircraft for relevant market segments. Several objectives are set in order to reach this target. The first objective is to provide an overview of the state of the art on the scientific background of the relation between aircraft design and operation and its climate impact. The second objective is to derive characteristic aircraft design requirements, based on statistical data analysis of the worldwide aircraft fleet and route structure for future Entries into Service using a comprehensive air traffic forecast model. The third objective is to develop CFAD for the use in the aircraft design optimization, which reliably represent the climate impact of CO2, NOx, H2O emissions, as well as contrail-cirrus effects. The fourth objective is to perform MDO with respect to the CFAD to find a set of operational parameters, design parameters and aircraft technologies that minimize the climate impact of the aircraft design using an existing MDO environment that applies the developed CFADs as objective function. The fifth and final objective is to perform an assessment of the aircraft designs chosen in order to quantify their impact on important metrics such as landing and take-off noise, emissions and cash operating cost. For this purpose, a higher-fidelity simulation integrating existing flight performance, emission and climate impact models is adapted and applied to simulate the aircraft design solution in an operational environment.
An extensive research of previously performed research projects dealing with the climate impact of aircraft design and aircraft operations was conducted and a summary report on the state of the art was prepared that provides the scientific background for the projects. Aspects of the report include e.g. the use of different climate metrics, temporal scales, but also the current knowledge on the relationships between aircraft design parameters and their impact on climate.
An analysis of the worldwide aircraft fleet and route structure in the future was done by adapting and applying an existing air traffic forecast model. The model was calibrated with 2019 flight movement data (unimpeded by COVID-19) and provided forecasted aircraft movements from the year 2019 (~2020) to 2050 in 5 years intervals.
Based on the analysis of the worldwide aircraft fleet utilization, the market segments that utilize aircraft types with seats greater than 250 were selected. These aircraft types were found to cover over 37% of the global ASK in 2019 and have the highest forecasted growth rate until 2050. Their contribution to climate impact (calculated with 2012 air traffic data) is approximately 39%, so they contribute substantially to aviation induced climate impact and are suitable for an optimization. Finally, on that basis, the GLOWOPT representative route network was defined.
The Top-Level Aircraft Requirements (TLARs) and design constraints were derived from previous studies on optimal operational conditions for mitigating climate impact and were adjusted to the selected market segment. They include Cruise Altitude and Mach number, Design Range, Take-off Field Length, Wingspan, Capacity and Approach Speed.
A suitable climate metric (Average Temperature Response over 100 years, ATR100) was selected and a sensitivity study on climate metrics is being performed concerning the type of metrics and different time horizons. An initial concept for the development of CFAD was developed, which is currently being refined.
Two aircraft concepts with different design range were defined and the design process of the reference aircraft has been initiated. The envelope of parameters, optimisation variables were tested in MDO framework for different objectives. At the moment, a set of nine design variables is proposed, consisting of two wing, five (turbofan) engine and two mission design variables. The first optimisations will target a tube-and-wing aircraft with turbofan engines. However, for the technology portfolio, technologies such as natural/hybrid laminar flow and propeller-based engines are considered.
• By the development of aircraft design-related CFAD, GLOWOPT will support the design of new aircraft with significantly reduced climate impact.
• The amount of CO2 and NOx emissions will be reduced by using those CFAD in the MDO process, but more importantly, the operating regime of the aircraft is changed such that the location/altitude of the emissions will be shifted to less climate sensitive regions.
• The increasing importance of non-CO2 effects of aviation can be responsibly considered in the development of next-generation aircraft.
• GLOWOPT will make sure that the CFADs are generated not solely on an academic basis but tailored to the characteristics of the future air traffic demand in terms of markets and design requirements.
• GLOWOPT is aiming to contribute to the competitiveness of the European Union and ultimately secure and improve mobility.
• GLOWOPT gives the possibility to address the full suite of climate impacts, beyond CO2 emissions in the CS2 TE. This enables assessments within the TE: First, a climate impact assessment of the emission inventories developed within the TE and second, a climate impact assessment of the technologies.

Both members of the GLOWOPT consortium are universities that do research and teaching in aerospace and air transportation systems, respectively. By nature, they utilize and exploit the knowledge and experience gained during the course of this project in order to
- further improve the state-of-the-art on environmentally-optimized aircraft design advance
- lectures on aircraft design and operations and thus educate MSc students, PhDs and Postdocs and provide data from the project for their research work
Schematic representation of the GLOWOPT approach
Basic Strategy for the development of Climate Functions for Aircraft Design (CFAD)