Search Results (586)

The aviation sector is under pressure to reduce greenhouse gas emissions. Proton exchange membrane fuel cell (PEMFC) systems are considered a promising option for sustainable aviation because of their high efficiency and suitability for electric propulsion. However, their performance deteriorates at high altitudes because reduced ambient pressure lowers the oxygen partial pressure at the cathode. This study investigated aviation PEMFC systems employing different air compression strategies under aircraft operating conditions. Three air supply configurations were examined: no compressor, a single-stage compressor, and a double-stage compressor. Among these, the double-stage configuration most effectively improved the reactant supply and stack output at high altitudes. Although the double-stage configuration increased compressor parasitic power consumption and required additional heat rejection through intercooling, its higher gross stack output compensated for these penalties and produced the highest net output. Achieving the same output with the no-compressor or single-stage compressor configuration would require additional cells and a larger stack. The system-specific power analysis showed that the double-stage configuration provided the most favorable mass-based performance. These results suggest that a double-stage-compressor configuration can be an effective air supply strategy for aviation PEMFC systems under high-altitude conditions. Full article

This paper presents a novel modular assembly concept for large-volume Carbon Fiber Reinforced Plastics (CFRP) hydrogen tanks, supporting the aviation sector’s transition toward sustainable propulsion. Adhering to VDI 2221 and 2222 design methodologies, four assembly concepts were developed and then evaluated by Airbus, FFT, and Fraunhofer IFAM, to determine the best fit for industrial application. The “Modular Assembly System on Linear Axes” was identified as the best solution, characterized by superior process robustness and efficiency. Utilizing dual linear axes for precise component handling and robotic guidance, this concept ensures structural integrity during joining while offering scalability and seamless integration into existing manufacturing infrastructures. Full article

Across four decades of AI deployment, the same six human challenges (trust calibration, reliance behavior, cognitive engagement, skill retention, accountability, and transparency) recur, yet fragmentation across research communities obscures this continuity and limits knowledge transfer. Functionally similar phenomena are repeatedly relabeled (a jangle fallacy): what aviation researchers call “automation complacency,” decision scientists call “algorithm appreciation,” and LLM researchers describe as “over-reliance.” This systematic review synthesizes 152 papers spanning aviation, healthcare, manufacturing/supply chain, and cross-domain contexts across three AI technology generations: decision support systems, autonomous systems, and large language model (LLM) agents. We introduce the Collaboration Convergence Framework (CCF), a 6 × 3 matrix with solution-maturity indicators that maps each challenge across generations. The framework shows that Gen 3 designers can transfer decades of evidence from automation and decision support research (particularly reliance calibration, cognitive forcing, and skill maintenance) rather than rediscovering them. Cross-generational synthesis also isolates three Gen 3 phenomena without direct precedent in earlier generations: epistemia (attributing genuine knowledge to LLMs based on surface fluency), attribution ambiguity in co-creation, and motivational withdrawal. We distill twelve transferable design principles and propose ten research directions, prioritizing skill-retention interventions and accountability frameworks. These findings carry direct sustainability implications aligned with Industry 5.0: protecting workforce capability under increasing automation (SDG 8), reducing duplicated research effort through cross-generational knowledge reuse (SDG 9), and supporting responsible deployment by treating collaboration risks as predictable rather than novel (SDG 12). The CCF provides conceptual infrastructure for cumulative learning across AI generations and industries. Full article

Sustainable aviation fuel (SAF) is widely recognized as a critical pathway for aviation decarbonization; however, its life-cycle carbon performance is highly sensitive to supply chain configurations. This study proposes a data-driven framework integrating life-cycle assessment (LCA) with a generative adversarial network (GAN) to model and optimize SAF supply chain pathways under structural constraints. A rule-constrained synthetic dataset comprising feasible pathways is constructed, incorporating feedstock sources, refinery locations, airport demand nodes, conversion technologies, transport modes, and distances. Each pathway is encoded into a numerical feature vector, and a GAN model is trained to learn the distribution of feasible configurations. Generated pathways are further validated through LCA-based post-processing to ensure physical feasibility and emission consistency. The results show that pathway-level carbon intensity varies significantly across configurations, with differences exceeding 30% under varying feedstock–transport combinations. The model successfully captures the multimodal distribution of carbon emissions and identifies structurally consistent low-carbon pathways. In particular, localized supply structures and reduced transport distances are found to play a dominant role in minimizing emissions. This study provides a scalable methodological framework for SAF pathway modeling and offers insights into supply chain design and spatial configuration for achieving aviation carbon reduction targets. Full article

The transition toward sustainable aviation fuels for unmanned aerial vehicle propulsion requires alternative fuel blends that reduce emissions while maintaining stable power generation. This study investigates the combustion performance, electrical output, emission behavior, and near-field pollutant dispersion of butanol–kerosene blends in a hybrid micro-turboprop propulsion platform representative of UAV applications. Conventional kerosene and three butanol–kerosene blends, containing 10%, 20%, and 30% butanol by volume, were tested under four operating regimes ranging from idle to approximately 2.5 kW electrical load. Exhaust gas temperature, CO, NO, NOx, SO₂, electrical power output, throttle response, and pollutant dispersion behavior were evaluated experimentally, while polynomial regression was applied to quantify throttle–power relationships. The results show that the 20% butanol blend provided the most favorable overall performance. Relative to conventional kerosene, B20 achieved approximately 4.8% higher electrical power output at equivalent throttle settings, reduced fuel demand by nearly 3.9%, and decreased the throttle requirement for 2 kW electrical output by almost 5%. In terms of emissions, B20 reduced CO formation across low and intermediate operating regimes while maintaining moderate NOx levels and stable exhaust gas temperature behavior. Increasing butanol content also improved plume homogenization: the anisotropy index decreased from 2.41 for B10 to 1.96 for B20 and 1.58 for B30, while high-concentration plume regions were reduced by up to 31%. However, B30 introduced stronger evaporative cooling, ignition delay effects, and reduced mid-load responsiveness. Overall, moderate butanol blending, particularly B20, represents the most balanced solution for reducing the environmental footprint of hybrid UAV micro-turboprop propulsion without significant performance penalties. Full article

Oblique detonation engines have been proposed for hypersonic propulsion because detonation-based heat addition can, in principle, provide rapid energy release with reduced total-pressure penalties. We investigate non-premixed injection/mixing of an RP-3 aviation-kerosene surrogate in a constrained supersonic channel and its impact on oblique-detonation initiation, stabilization, and static pressure gain. Numerical simulations are performed for a Mach 8 inflow representative of a 30 km altitude condition using an OpenFOAM v7-based reacting-flow solver. We analyze the pressure-gain process following detonation onset, quantify the effects of the inducer-ramp angle, and qualitatively assess the predicted initiation/stabilization trends against direct-connect hot-fire experiments. The results show that non-premixed injection into a supersonic crossflow yields limited mixing over the available mixing length and results in a strongly stratified inflow to the combustor. In the constrained passage, a train of reflected shocks forms and progressively reduces the total-pressure recovery factor along the mixing section, which asymptotically approaches ~0.49. In the combustor, the inducer-ramp angle controls whether and how a stabilized oblique detonation can be established. For a 25° ramp, no self-sustained ODW is obtained under the present conditions, whereas stabilized ODWs are observed for 30° and 35° ramps, exhibiting abrupt and smooth topologies, respectively. These initiation thresholds and stabilized morphologies show qualitative consistency with the direct-connect observations. Due to fuel stratification, pressure gain varies among streamlines but consistently follows a “primary compression–plateau–secondary pressure rise” sequence; the secondary stage contributes approximately 17.54–27.98% of the static pressure rise. Full article

The aviation sector is accelerating the transition toward low-carbon propulsion, and Sustainable Aviation Fuels (SAFs) represent a key leverage to reduce lifecycle emissions without modifying existing turbine architectures. Microturbines offer an effective and low-cost platform for assessing SAF behaviour under engine-representative conditions. In this work, a zero-dimensional performance and emission model of the GTM-140 microturbine was developed in GSP and validated against experimental data at 70,000–112,000 rpm for Jet A-1 and HEFA paraffinic blends. The model reproduces thrust and fuel-flow trends with good fidelity, with deviations typically below 6% across all operating points. Introducing 50% HEFA consistently reduces fuel consumption, leading to a TSFC decrease of 3–6%, with the strongest effect at high rotational speed, where compressor efficiency is highest. CO emission indices decrease by 6–9% at mid-load and converge at full power due to enhanced oxidation, while NO_x increases by 6–15%, driven by the higher adiabatic flame temperature associated with HEFA’s increased H/C ratio and heating value. These results confirm that simplified 0D modelling can reliably capture performance and emission trends of SAF-fuelled microturbines and demonstrate the dual effect of HEFA: improved combustion efficiency and CO reduction, at the expense of moderately higher NO_x formation. Full article

The rapid growth of global air traffic places the aviation industry under dual pressure: meeting increasing demand for aircraft while substantially reducing life-cycle environmental impacts. As advancements in aerodynamics, propulsion, and the adoption of lightweight composite materials continue to reduce operational fuel burn, the relative significance of manufacturing and End-of-Life phases is expected to increase. This study develops a low-fidelity aerostructural optimization framework for high aspect ratio wings that integrates life-cycle considerations into early-stage material selection. Using aluminum and carbon fiber reinforced polymers (CFRP) as reference materials, the framework quantifies trade-offs in mass savings, fuel burn, and CO₂ equivalent emissions across production, operations, and disposal phases. Results show that while CFRP offers substantial benefits in structural efficiency and operational emissions, aluminum performs more favorably in End-of-Life scenarios due to its high recyclability. The study further evaluates the potential of Sustainable Aviation Fuel (SAF) blending as a complementary decarbonization lever, revealing that moderate SAF adoption can offset part of the operational advantage of CFRP. Overall, this work demonstrates the importance of coupling material choice with life-cycle assessment in aerostructural design and outlines a pathway toward multi-objective optimization frameworks that balance performance with environmental sustainability. Full article

Sustainability in aviation is crucial to address the environmental issues and climate impacts associated with the aviation industry. Moreover, efficient operations are critical affected by increasing air traffic volumes. In this context, analyzing aircraft fuel consumption and efficiency is necessary. In particular, fuel consumption per unit may vary depending on route characteristics, which should be considered when analyzing and assessing aircraft fuel consumption. In this study, aircraft fuel consumption was estimated using trajectory data, and route-dependent differences in fuel consumption were subsequently analyzed. Fuel consumption per unit distance and unit time were calculated for each analyzed route, and the significance of differences between routes was tested using a one-way analysis of variance. A post hoc test was conducted to identify specific differences between routes, along with an effect size analysis. The results indicated that differences in fuel consumption per distance and fuel consumption per time between different routes were both statistically significant. In the detailed analysis, eta-squared was calculated to assess the proportion of total variance in fuel consumption explained by differences among routes. Furthermore, post hoc tests were conducted to identify which route pairs exhibited statistically significant differences in fuel consumption. The results of this study confirm that aircraft fuel consumption characteristics can vary depending on the route. Therefore, route-dependent differences must be considered, and both macroscopic and microscopic assessments at the route level must be performed when assessing aircraft fuel consumption. Full article

Ice accumulation on critical infrastructure surfaces threatens operational safety in aviation, power transmission, and transportation systems. Conventional anti-icing and deicing strategies, such as chemical deicers and energy-intensive active heating, have inherent drawbacks. These include environmental pollution, high energy consumption, and low efficiency. In recent years, photothermal-responsive extremely water-repellent surfaces have attracted widespread attention. They can harvest renewable solar energy and achieve efficient anti-icing and deicing through tailored interfacial wetting properties. This review summarizes photothermal extremely water-repellent surfaces based on the “water as a lubricating layer” strategy. This strategy reduces ice adhesion strength and enables low-energy deicing. It works by forming a continuous lubricating film via photothermally induced interfacial meltwater. We discuss photothermal conversion mechanisms and strategies to enhance performance for stable lubricating film formation. We also analyze the stagewise physics of anti-icing and deicing, focusing on the interfacial tribological behavior of the water film. Key engineering challenges are addressed, including mechanical durability and all-weather applicability. Finally, we clarify future research directions for industrial translation. This review aims to provide theoretical insights and technical pathways for developing next-generation anti-icing and deicing surfaces that are efficient, eco-friendly, and sustainable. Full article

Decarbonizing aviation requires innovative propulsion technologies and thermodynamic systems that enable efficient, sustainable energy conversion. The Institute of Thermodynamics at Leibniz University Hannover is engaged in several interdisciplinary research projects focusing on advanced, low-emission aircraft propulsion solutions. Two major areas of research are presented: high-temperature solid oxide fuel cells (SOFCs) for hybrid aircraft propulsion and thermal management systems for proton exchange membrane (PEM) fuel cell propulsion, including additively manufactured heat exchangers for aviation applications. These research activities contribute to the technological foundation of more climate-friendly aviation. Concepts are investigated through numerical simulations, experiments, and system-level analyses to develop future propulsion solutions. This paper provides a comprehensive overview of the Institute of Thermodynamics’ ongoing research and the synergies between its various fields. It offers insights into the challenges and opportunities of more sustainable aviation technologies. Full article

As the aviation industry explores sustainable solutions for next-generation aircraft, the strut-braced wing (SBW) concept has emerged as a promising configuration, combining the enhanced aerodynamic efficiency of high-aspect-ratio (HAR) wings with a significant reduction in wing structural weight compared to conventional cantilever designs. Given the inherent aerodynamics and structural complexities of SBW concepts, developing innovative design methodologies is essential for fully investigating their potential. This work presents a low-fidelity, two-fold design methodology combining an overall aircraft design framework with finite element structural analysis. The approach enables overall aircraft design (OAD) sizing, exploration, and optimization of regional strut-braced wing configurations and assessing the effects of strut connections and jury on the wing’s static and buckling behavior. Trade-off and optimization studies based on the reference ATR-72 aircraft led to an optimal SBW configuration with an aspect ratio of 17.64 and a strut position ratio of 0.543, achieving reductions of about 24% in wing weight and 6.78% in fuel burn. The structural analysis of the optimized SBW indicates that a clamped–clamped strut connection provides superior buckling performance, and incorporating a jury strut effectively mitigates buckling issues while achieving approximately 20% wing weight reduction compared to the configuration without a jury. Full article

Digital transformation has become one of the key drivers of airport sustainability development; however, existing digital maturity frameworks are not fully tailored to the aviation context, particularly within Australia. This study built a conceptual digital maturity model for Australian airports by integrating ISO/IEC maturity framework with the Airport 1.0–5.0 concept. A structured literature review informed the dimension formulation, and the model was validated through case studies of Australia’s Big 4 airports and one regional airport. The findings show that the Big 4 airports have largely achieved Airport 4.0 maturity, while Cairns Airport demonstrates maturity between Airport 2.5 and 3.0. These results confirm the model’s applicability and discriminative capability across diverse operational scales. The proposed model offers a practical, context-specific framework for benchmarking, planning, and guiding digital transformation initiatives across Australian airports. Full article

One of the fundamental aspects of achieving sustainability in aviation is reducing aircraft emissions. While the effects of CO₂ have been studied extensively, it is crucial to also consider non-CO₂ emissions. This paper presents the fundamental ideas of the research developed to analyse the path to sustainability in aviation within the framework of the European Environmentally Friendly Aviation for All Classes of Aircraft (EFACA) project. Nine scenarios are considered in the analysis: two reference scenarios, the EFACA base scenario and six EFACA variations scenarios. The EFACA base scenario considers the project’s proposal for sustainable aviation for all classes of aircraft. Additionally, the methodology followed in the analysis is presented. The decisions made to calculate carbon and total emissions, costs and investments, and economic effects are specified. The analytical approaches adopted are also discussed. Projections for the different scenarios up to 2050 are calculated and comparative and sensitivity analyses performed. The paper presents the logic behind each stage and demonstrates how this methodological approach can be used as a valuable tool for analysing the prospects for a more sustainable aviation in terms of reducing emissions. Full article

This paper reviews selected biofuels that are currently in use, as well as fuels considered promising, for powering compression-ignition (CI) engines, including Common Rail systems. The review focuses on fuel properties, production pathways, operational compatibility, and the effects on engine performance and exhaust emissions. The objective is to systematize the current state of knowledge on biodiesel, hydrotreated vegetable oil (HVO), biomass-to-liquid (BtL), F-34, and sustainable aviation fuel (SAF), and to identify their key advantages, implementation constraints, and research gaps relevant to transport and power-generation applications. The paper compiles and compares published studies on fuel production routes and on the consequences of fuel use in CI engines with respect to performance and pollutant emissions. As an outcome, the available evidence is synthesized, fuels with the highest implementation potential are indicated in the context of emission reduction while maintaining required operational functionality, and priority areas for further research are highlighted, including the still insufficiently characterized effects of SAF on CI engine operation and emissions. Full article