Bauhaus Luftfahrt

PurposeRevolutionary advances in aircraft technology and performance are needed for fuel-efficient and sustainable next-generation air transportation. This study aims to explore the influence of integrating distributed propulsion with ultra-high aspect ratio (AR) wings (UHARW) on the realization of fully electric regional aviation.Design/methodology/approachThe strut-braced wing (SBW) configuration is advantageous for UHARW due to its additional support. A conceptual design and analysis framework for UHARW aircraft with SBW and distributed propulsion configurations is developed by enhancing and integrating several methods and tools. Based on the mission profile and top-level requirements, a fully electric regional SBW aircraft with distributed propulsion is designed and analyzed.FindingsIntegrating distributed propulsion with a high AR SBW configuration in a fully electric regional aircraft results in notable energy efficiencies. The design achieves a 2.85% increase in the lift-to-drag ratio and a 2.62% reduction in drag during cruise. Sensitivity analysis indicates optimal performance with an AR up to 22, beyond which structural weight penalties diminish benefits. The aircraft’s energy efficiency improves by 9.9% during climb and 6% during cruise, highlighting the importance of propulsion integration.Practical implicationsThis research provides a viable framework for designing fully electric regional aircraft by integrating distributed propulsion with high AR SBW configurations. The findings provide practical guidance for enhancing energy efficiency and reducing structural weight, supporting the development of more sustainable and efficient aircraft designs.Social implicationsThe findings support the development of sustainable aviation technologies, potentially reducing the environmental footprint of regional air travel and contributing to global efforts toward greener transportation solutions.Originality/valueThis study presents a comprehensive methodology for designing and analyzing UHARW aircraft with SBW and distributed propulsion, contributing to the feasibility assessment of fully electric regional aviation.

Beim Annehmen eines Erbes vom Verstorbenen sollte der Erbe darauf vorbereitet sein, dass neben den notariell beglaubigten Vermögenswerten des Erblassers auch die Möglichkeit besteht, dass Kreditverpflichtungen ab dem Zeitpunkt des Erwerbs der Erbrechte übertragen werden können.

The concept of the water, energy, and food (WEF) security nexus envisions the holistic development of WEF sectors, considering social, economic, and environmental aspects. Ensuring WEF security is challenging due to positive and negative interactions among the sectors. The nexus approach provides a framework to identify these interactions and to address this challenge. Despite its usefulness, however, only a limited number of nexus studies have discussed the quantitative interactions among the nexus elements. Furthermore, the varying nexus relationships across different countries have rarely been analysed and compared. To fill this gap, we systematically analysed WEF interactions for East and Southeast Asia by using open data sources at the country scale. We defined positive and negative correlations between the WEF security indicators as synergies and trade-offs, respectively. We identified the most positively and negatively influential indicators in the WEF networks using the results of our correlation analysis. Our results show that more trade-off relations than synergistic relations exist within and among the WEF sectors for East and Southeast Asia at the regional scale, e.g., interactions between energy-energy, energy-water, food-water, and water-water. The country-level analysis reveals that the percentages of synergies and trade-offs vary across countries. Some countries (e.g., China, Mongolia, and Myanmar) have more links in the synergy network. In contrast, others (e.g., Malaysia, the Republic of Korea, and Vietnam) have more links in the trade-off network. Our analysis highlights the strategies for promoting renewable and clean energy and discouraging fossil fuel consumption will leverage the WEF security nexus at both regional and country scales in the East and Southeast Asian regions.

Agriculture in India accounts for 18% of greenhouse gas (GHG) emissions and uses significant land and water. Various socioeconomic factors and food subsidies influence diets in India. Indian food systems face the challenge of sustainably nourishing the 1.3 billion population. However, existing studies focus on a few food system components, and holistic analysis is still missing. We identify Indian food systems covering six food system components: food consumption, production, processing, policy, environmental footprints, and socioeconomic factors from the latest Indian household consumer expenditure survey. We identify 10 Indian food systems using k-means cluster analysis on 15 food system indicators belonging to the six components. Based on the major source of calorie intake, we classify the ten food systems into production-based (3), subsidy-based (3), and market-based (4) food systems. Home-produced and subsidized food contribute up to 2000 kcal/consumer unit (CU)/day and 1651 kcal/CU/day, respectively, in these food systems. The calorie intake of 2158 to 3530 kcal/CU/day in the food systems reveals issues of malnutrition in India. Environmental footprints are commensurate with calorie intake in the food systems. Embodied GHG, land footprint, and water footprint estimates range from 1.30 to 2.19 kg CO2eq/CU/day, 3.89 to 6.04 m2/CU/day, and 2.02 to 3.16 m3/CU/day, respectively. Our study provides a holistic understanding of Indian food systems for targeted nutritional interventions on household malnutrition in India while also protecting planetary health.

View Video Presentation: https://doi.org/10.2514/6.2022-3738.vid The overarching goal in the GNOSIS project is to holistically evaluate the potential through aircraft propulsion system electrification at the two temporal assessment horizons in 2025 and 2050. In this context, one of the evaluation parameters is the CO2 equivalent emissions associated with aircraft operations. In this study, the aforementioned emissions are calculated for two electrified aircraft configurations with 19 seats passenger capacity, determined in previous project phases. Afterwards, the emissions are compared to those of the aircraft operated either with conventional kerosene or sustainable aviation fuels from different production pathways. In order to achieve the set goal, two main steps are carried out. First, the MICADO framework for aircraft design and evaluation is extended with new models for the required propulsion system components. Second, based on a literature review, the CO2 equivalent well-to-wheel emissions associated with production and combustion per kilogram of fuel are determined for kerosene, grid electricity and three sustainable aviation fuels. Results show that the partial turboelectric propulsion system selected for 2025 increases the overall system complexity significantly without providing noteworthy advantages over a conventionally powered reference configuration. At the same time, the great potential of SAF becomes apparent if an efficient production path is chosen. According to the results for the year 2050, the use of fossil kerosene for 19-seat passenger aircraft should be dispensed with. The kerosene alternatives investigated here, i.e. combusting 100% SAF in gas turbines or using liquid hydrogen in fuel cells, reduce the equivalent CO2 emissions associated with the production and combustion of the fuels significantly. Savings range between 45 to 80% depending on the main source of energy.

A fuel cell—gas turbine hybrid propulsion concept is introduced and initially assessed. The concept uses the water mass flow produced by a hydrogen fuel cell in order to improve the efficiency and power output of the gas turbine engine through burner steam injection. Therefore, the fuel cell product water is conditioned through a process of condensation, pressurization and re-vaporization. The vaporization uses the waste heat of the gas turbine exhaust. The functional principles of the system concept are introduced and discussed, and appropriate methodology for an initial concept evaluation is formulated. Essential technology fields are surveyed in brief. The impact of burner steam injection on gas turbine efficiency and sizing is parametrically modelled. Simplified parametric models of the fuel cell system and key components of the water treatment process are presented. Fuel cell stack efficiency and specific power levels are methodically derived from latest experimental studies at the laboratory scale. The overall concept is assessed for a liquid hydrogen fueled short-/medium range aircraft application. Block fuel savings of up to 7.1% are found for an optimum design case based on solid oxide fuel cell technology. The optimum design features a gas turbine water-to-air ratio of 6.1% in cruise and 62% reduced high-level NOx emissions.

• We study welfare and environmental effects of electric modes in cities. • Electric cars reduce CO 2 emissions despite increasing travel and congestion. • The resulting welfare losses may dominate the gains from reducing CO2. • Welfare effects of UAM depend on initial mode choice and the way of introduction. • Substituting gasoline (electric) cars, UAM decreases (increases) emissions. This research aims to assess the broader impact of electric mobility in urban settlements, paying attention to both electrified ground and air transport. Considering electric cars as well as electric passenger drones, often referred to as UAM (urban air mobility), we use an urban spatial computable general equilibrium model to assess the welfare and environmental impacts of a transition to electric mobility. A numerical simulation of the model shows that a transition from gasoline to electric cars yields major emission reductions, while leading to welfare losses due to tax-induced market distortions. Introducing UAM into a gasoline-car city leads to marginal overall welfare gains. Introducing UAM into a city with electric cars results in welfare losses. While introducing UAM as an alternative to gasoline cars decreases CO 2 emissions, the introduction of UAM as alternative to electric cars leads to increasing emissions.