Exploration and Sizing of a Large Passenger Aircraft with Distributed Electric Ducted Fans

In order to reduce the CO2 emissions, a disruptive concept in aircraft propulsion has to be considered. As studied in the past years hybrid distributed electric propulsion is a promising option. In this work the feasibility of a new concept aircraft, using this technology, has been studied. Two different energy sources have been used: fuel based engines and batteries. The latters have been chosen because of their exibility during operations and their promising improvements over next years. The technological horizon considered in this study is the 2035: thus some critical hypotheses have been made for electrical components, airframe and propulsion. Due to the uncertainty associated to these data, sensivity analyses have been performed in order to assess the impact of technologies variations. To evaluate the advantages of the proposed concept, a comparison with a conventional aircraft(EIS 2035), based on evolutions of today's technology (airframe, propulsion, aerodynamics)has been made

Preliminary Sizing of a Medium Range Blended Wing-Body using a Multidisciplinary Design Analysis Approach

The aviation's goal for the next decades is to drastically reduce emissions, but to achieve this goal a breakdown in aircraft design have to be considered. One of the most promising concept is the Blended Wing-Body, which integrates aerodynamics, propulsion and structure, and has a better aerodynamics efficiency, thanks to the reduction of the wetted surfaces. In this work the feasibility of a short/medium range BWB with 150 passengers (A320 type aircraft, Entry Into Service 2035) is studied, considering different disciplines into the sizing process. To supply the lack of reference data, an approach that goes from high fidelity to validate low fidelity models has been set up. Also certification aspects have been taken into account in an off-design analysis. To evaluate the advantages of the proposed concept, it has been compared with an aircraft of the same class, the A320 Neo, resized to match the EIS2035 hypothesis: results show that the BWB is a concept that shows a gain in fuel consumption, especially on longer ranges

Multidisciplinary Design Optimization Framework with Coupled Derivative Computation for Hybrid Aircraft

Hybrid-electric aircraft are a potential way to reduce the environmental footprint of aviation. Research aimed at this subject has been pursued over the last decade; nevertheless, at this stage, a full overall aircraft design procedure is still an open issue. This work proposes to enrich the procedure for the conceptual design of hybrid aircraft found in literature through the definition of a multidisciplinary design optimization (MDO) framework aimed at handling design problems for such kinds of aircraft. The MDO technique has been chosen because the hybrid aircraft design problem shows more interaction between disciplines than a conventional configuration, and the classical approach based on multidisciplinary design analysis may neglect relevant features. The procedure has been tested on the case study of a single-aisle aircraft featuring hybrid propulsion with distributed electric ducted fans. The analysis considers three configurations (with 16, 32, and 48 electric motors) compared with a conventional baseline at the same 2035 technological horizon. To demonstrate the framework’s capability, these configurations are optimized with respect to fuel and energy consumption. It is shown that the hybrid-electric concept consumes less fuel/energy when it flies on short range due to the partial mission electrification. When one increases the design range, penalties in weight introduced by hybrid propulsion overcome the advantages of electrified mission segment: the range for which hybrid aircraft have the same performance of the reference conventional aircraft is named the “breakdown range.” Starting from this range, the concept is no longer advantageous compared to conventional aircraft. Furthermore, a tradeoff between aerodynamic and propulsive efficiency is detected, and the optimal configuration is the one that balances these two effects. Finally, multiobjective optimization is performed to establish a tradeoff between airframe weight and energy consumption

Accelerating the path towards carbon-free aviation

This paper, created by a group of aviation and energy experts from renowned universities and research centres in Europe, who oversee the fields of energy carriers, energy storage and conversion, propulsion, aerodynamics, flight mechanics, controls, structures, materials, multidisciplinary design, and life‐cycle engineering, aims to give an overview and assessment of promising future technologies. The paper therefore identifies the potential as well as research demands of these technologies on the path to a sustainable and more environmentally friendly aviation

Prevalence, associated factors and outcomes of pressure injuries in adult intensive care unit patients: the DecubICUs study

Funder: European Society of Intensive Care Medicine; doi: http://dx.doi.org/10.13039/501100013347Funder: Flemish Society for Critical Care NursesAbstract: Purpose: Intensive care unit (ICU) patients are particularly susceptible to developing pressure injuries. Epidemiologic data is however unavailable. We aimed to provide an international picture of the extent of pressure injuries and factors associated with ICU-acquired pressure injuries in adult ICU patients. Methods: International 1-day point-prevalence study; follow-up for outcome assessment until hospital discharge (maximum 12 weeks). Factors associated with ICU-acquired pressure injury and hospital mortality were assessed by generalised linear mixed-effects regression analysis. Results: Data from 13,254 patients in 1117 ICUs (90 countries) revealed 6747 pressure injuries; 3997 (59.2%) were ICU-acquired. Overall prevalence was 26.6% (95% confidence interval [CI] 25.9–27.3). ICU-acquired prevalence was 16.2% (95% CI 15.6–16.8). Sacrum (37%) and heels (19.5%) were most affected. Factors independently associated with ICU-acquired pressure injuries were older age, male sex, being underweight, emergency surgery, higher Simplified Acute Physiology Score II, Braden score 3 days, comorbidities (chronic obstructive pulmonary disease, immunodeficiency), organ support (renal replacement, mechanical ventilation on ICU admission), and being in a low or lower-middle income-economy. Gradually increasing associations with mortality were identified for increasing severity of pressure injury: stage I (odds ratio [OR] 1.5; 95% CI 1.2–1.8), stage II (OR 1.6; 95% CI 1.4–1.9), and stage III or worse (OR 2.8; 95% CI 2.3–3.3). Conclusion: Pressure injuries are common in adult ICU patients. ICU-acquired pressure injuries are associated with mainly intrinsic factors and mortality. Optimal care standards, increased awareness, appropriate resource allocation, and further research into optimal prevention are pivotal to tackle this important patient safety threat

Correction to: Prevalence, associated factors and outcomes of pressure injuries in adult intensive care unit patients: the DecubICUs study

The original version of this article unfortunately contained a mistake

Prevalence, associated factors and outcomes of pressure injuries in adult intensive care unit patients: the DecubICUs study

Funder: European Society of Intensive Care Medicine; doi: http://dx.doi.org/10.13039/501100013347Funder: Flemish Society for Critical Care NursesAbstract: Purpose: Intensive care unit (ICU) patients are particularly susceptible to developing pressure injuries. Epidemiologic data is however unavailable. We aimed to provide an international picture of the extent of pressure injuries and factors associated with ICU-acquired pressure injuries in adult ICU patients. Methods: International 1-day point-prevalence study; follow-up for outcome assessment until hospital discharge (maximum 12 weeks). Factors associated with ICU-acquired pressure injury and hospital mortality were assessed by generalised linear mixed-effects regression analysis. Results: Data from 13,254 patients in 1117 ICUs (90 countries) revealed 6747 pressure injuries; 3997 (59.2%) were ICU-acquired. Overall prevalence was 26.6% (95% confidence interval [CI] 25.9–27.3). ICU-acquired prevalence was 16.2% (95% CI 15.6–16.8). Sacrum (37%) and heels (19.5%) were most affected. Factors independently associated with ICU-acquired pressure injuries were older age, male sex, being underweight, emergency surgery, higher Simplified Acute Physiology Score II, Braden score 3 days, comorbidities (chronic obstructive pulmonary disease, immunodeficiency), organ support (renal replacement, mechanical ventilation on ICU admission), and being in a low or lower-middle income-economy. Gradually increasing associations with mortality were identified for increasing severity of pressure injury: stage I (odds ratio [OR] 1.5; 95% CI 1.2–1.8), stage II (OR 1.6; 95% CI 1.4–1.9), and stage III or worse (OR 2.8; 95% CI 2.3–3.3). Conclusion: Pressure injuries are common in adult ICU patients. ICU-acquired pressure injuries are associated with mainly intrinsic factors and mortality. Optimal care standards, increased awareness, appropriate resource allocation, and further research into optimal prevention are pivotal to tackle this important patient safety threat

Amélioration du processus de conception avion en prenant en compte les contraintes de certification et des simulations de mission complètes

In the field of civil transport aircraft, environmental constraints set challenging goals in terms of fuel consumption for the next generations of airplanes. With the “tube and wing” configuration offering low expectations on further improvements, disruptive vehicle concepts including new technologies are investigated. However, little information on such architectures is available in the early phases of the design process. Thus, research in Aircraft Design aims at adding knowledge in the Multidisciplinary Design Analysis.This objective is currently achieved with different approaches: implementation of Multidisciplinary Design Optimization, addition of accuracy through high fidelity analyses, introduction of new disciplines or systems and uncertainty management. In a preliminary study, the optimization of an innovative transport aircraft system based on a monolithic architecture and advanced structural models has been completed. The subsequent analysis of the outcomes highlighted specific needs towards the design of a viable concept. This research proposes then to add knowledge through an expansion of the Multidisciplinary Design Analysis and Optimization with a new Certification Constraint Module and full simulation capabilities.Following the development of the Certification Constraint Module (CCM), its capabilities have been used to perform four optimization problems associated to a conventional civil transport aircraft based on the ONERA / ISAE-SUPAERO sizing tool called FAST. Facilitated by the Graphical User Interface of the CCM, the setup time of these optimizations has been reduced and the results clearly confirmed the necessity to consider certification constraints very early in the design process in order to select the most promising concepts.To achieve full simulation capabilities, the multidisciplinary analysis within FAST had to be enhanced. First, the aerodynamics analysis tool has been modified so that necessary coefficients for a 6 Degrees-of-Freedom model could be generated. Second, a new module computing inertia properties has been added. Last, the open source simulator JSBSim has been used including different control laws for stability augmentation and automated navigation. The comparisons between flight trajectories obtained with FAST and real aircraft data recorded with ADS-B antenna confirmed the validity of the approach.Pour les prochaines générations d'avions de transport civil, les contraintes environnementales fixent des objectifs très ambitieux au niveau de la consommation de carburant. Avec une configuration classique optimisée pendant des décennies offrant peu de marges d’amélioration, de nouveaux concepts basés sur des configurations disruptives et/ou des technologies innovantes sont étudiés. Cependant, peu d'informations sur ces architectures sont disponibles dans les premières phases du processus de conception. Ainsi, les travaux de recherche en Conception Avion visent à ajouter des connaissances supplémentaires au sein de l'analyse multidisciplinaire. Actuellement, différentes approches sont utilisées: implémentation de boucles d'optimisation multidisciplinaire, ajout de précision grâce à des analyses haute-fidélité, introduction de nouvelles disciplines ou systèmes et gestion de l'incertitude. Suite à l’analyse des résultats obtenus lors d’une première optimisation d’un avion de transport utilisant un système d’assistance au sol basée sur une formulation monolithique et des modèles d’analyse structure avancés, des besoins spécifiques pour le dimensionnement d’un véhicule viable ont été identifiés. Ainsi, cette thèse propose d’ajouter de la connaissance au sein du processus de conception et d’optimisation via l’implémentation d’un nouveau module associé aux contraintes de certification et de capacités de simulations de mission. Développé entièrement dans le cadre de ces travaux, le module des contraintes de certification (CCM) a été utilisé pour résoudre quatre problèmes d'optimisation associés à un avion de transport civil classique basés sur l'outil de dimensionnement ONERA / ISAE-SUPAERO appelé FAST. Grâce aux fonctionnalités du CCM, le temps d'implémentation de ces optimisations a été réduit et les résultats ont clairement confirmé la nécessité de prendre en compte les contraintes de certification très tôt dans le processus de conception. Afin de mettre en place des capacités de simulation complète, l'analyse multidisciplinaire au sein de FAST a dû être revue : Tout d’abord, l'outil d'analyse aérodynamique a été modifié afin de générer les coefficients nécessaires pour un modèle à 6 degrés de liberté. Ensuite, un module de calcul des inerties a été ajouté. Enfin, le simulateur open source JSBSim a été utilisé avec différentes boucles de contrôle agissant sur la stabilité et la navigation

Innovative Airport and ATM Concept: (Operating an Endless Runway)

This paper presents an innovative and radical new concept for future airport operations, consisting of an airport with one circular circumventing runway, called The Endless Runway. This runway is used for take-off and landing in any direction from any point on the circle and offers through this the unique characteristic a sustainable capacity in all wind conditions through the possibility for an aircraft to operate with headwind during the take-off and landing phase. By placing airport facilities inside the circle, the airport will be more compact, runway crossings can be avoided and taxiing aircraft will be able to shorten their global trajectory through optimised arrival and departure routes. The project, the Endless Runway, is partly funded under EC FP

Improvement of the Aircraft Design process for Air Traffic Management evaluations

International audienceIn the field of Aircraft Design, new transport concepts rely heavily on aero-propulsive effects with the objective of providing step changes in terms of energy consumption. Given the strong dependency of the level of lift with respect to engine settings, there is an added value for the designers to complete full simulations of the operational mission to verify the viability of the selected architecture. Regarding Air Traffic Management, the need for more accurate trajectories as well as solutions to characterize new aircraft in the air space has been identified. Taking the opportunity of these shared requirements, the authors present in this paper the coupling between a conceptual design sizing tool and an ATM simulator. The objective is to pave the way for future optimizations of the global system where aircraft would be designed taking into account real flight routes defined by ATM constraints. To validate the simulation model generated by the sizing code, resulting climb trajectories as well as initial cruise phases are compared with real flight traces recorded with an ADS-B antenna