Methodology for sizing and optimising a Blended Wing-Body with distributed electric ducted fans

The increase of air traffic in the last decades and its projections pose a key challenge towards the carbon neutral growth objective. To cope with this societal goal, there is a need for disruptive air transport aircraft concepts featuring new technologies with low environmental impact. Such future air vehicle relies on the various interactions between systems, disciplines and components. This Ph.D. research thus focuses on the development of a methodology dedicated to the exploration and performance evaluation of unconventional configurations using innovative propulsion concepts. The use case to be considered is the optimisation at conceptual level of a Blended Wing-Body with distributed electric propulsion, a promising concept which combines high aerodynamic performances and benefits from electric propulsion. The optimisation process based on FAST, the ISAE-SUPAERO / ONERA aircraft sizing tool, has been implemented within OpenMDAO, the NASA open-source multidisciplinary analysis and optimisation framework. With the idea of a progressive enhancement of the multidisciplinary design analysis and a better capture of the different effects, the two pioneering elements have been studied separately. First, the classical process has been revised to take into account the new hybrid powerplant. Second, a methodology has been revised to consider a radically new airframe design. Last, a design process featuring both innovative aspects has been developed to investigate a Blended Wing Body concept with distributed electric propulsion. Concerning the design process, results show that the use of gradients in the optimisation procedure speeds up the process against a gradient-free method up to 70%. This is an important gain in time that facilitates designer’s tasks. For the disruptive concept performances, results have been compared to the ones obtained for a conventional A320 type aircraft based on the same top level requirements and technological horizon. Overall, the hybrid electric propulsion concept is interesting as it allows zero emissions for Landing/Take-Off operations, improving the environmental footprint of the aircraft: fuel can be saved for missions below a certain range. This limitation is associated to the presence of batteries: indeed they introduce indeed a relevant penalty in weight that cannot be countered by benefits of electrification for longer range. Additional simulations indicate that a Blended Wing-Body concept based on a turbo-electric only architecture is constantly performing better than the baseline within the limits of the assumptions

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

Upper trust bound feasibility criterion for mixed constrained Bayesian optimization with application to aircraft design

Bayesian optimization methods have been successfully applied to black box optimization problems that are expensive to evaluate. In this paper, we adapt the so-called super efficient global optimization algorithm to solve more accurately mixed constrained problems. The proposed approach handles constraints by means of upper trust bound, the latter encourages exploration of the feasible domain by combining the mean prediction and the associated uncertainty function given by the Gaussian processes. On top of that, a refinement procedure, based on a learning rate criterion, is introduced to enhance the exploitation and exploration trade-off. We show the good potential of the approach on a set of numerical experiments. Finally, we present an application to conceptual aircraft configuration upon which we show the superiority of the proposed approach compared to a set of the state-of-the-art black box optimization solvers

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

Méthodologie pour le dimensionnement et l'optimisation d'un corps d'aile mixte avec propulsion électrique distribuée

The increase of air traffic in the last decades and its projections pose a key challenge towards the carbon neutral growth objective. To cope with this societal goal, there is a need for disruptive air transport aircraft concepts featuring new technologies with low environmental impact. Such future air vehicle relies on the various interactions between systems, disciplines and components. This Ph.D. research thus focuses on the development of a methodology dedicated to the exploration and performance evaluation of unconventional configurations using innovative propulsion concepts. The use case to be considered is the optimisation at conceptual level of a Blended Wing-Body with distributed electric propulsion, a promising concept which combines high aerodynamic performances and benefits from electric propulsion.The optimisation process based on FAST, the ISAE-SUPAERO / ONERA aircraft sizing tool, has been implemented within OpenMDAO, the NASA open-source multidisciplinary analysis and optimisation framework.With the idea of a progressive enhancement of the multidisciplinary design analysis and a better capture of the different effects, the two pioneering elements have been studied separately.First, the classical process has been revised to take into account the new hybrid powerplant. Second, a methodology has been revised to consider a radically new airframe design. Last, a design process featuring both innovative aspects has been developed to investigate a Blended Wing Body concept with distributed electric propulsion.Concerning the design process, results show that the use of gradients in the optimisation procedure speeds up the process against a gradient-free method up to 70%. This is an important gain in time that facilitates designer’s tasks. For the disruptive concept performances, results have been compared to the ones obtained for a conventional A320 type aircraft based on the same top level requirements and technological horizon. Overall, the hybrid electric propulsion concept is interesting as it allows zero emissions for Landing/Take-Off operations, improving the environmental footprint of the aircraft: fuel can be saved for missions below a certain range. This limitation is associated to the presence of batteries: indeed they introduce indeed a relevant penalty in weight that cannot be countered by benefits of electrification for longer range. Additional simulations indicate that a Blended Wing-Body concept based on a turbo-electric only architecture is constantly performing better than the baseline within the limits of the assumptions.L'augmentation du trafic aérien au cours des dernières décennies et ses prévisions constituent un défi majeur pour arriver à une croissance neutre en carbone. Pour atteindre cet objectif sociétal, il est nécessaire de définir, en rupture avec les configurations actuelles, des concepts d'avion de transport intégrant de nouvelles technologies avec au final un impact minimal sur l'environnement. Ces futurs véhicules aériens reposent entre autres sur diverses interactions entre systèmes, disciplines et composants. Aussi, ces travaux de recherche se focalisent sur le développement d'une méthodologie dédiée à l'exploration et à l'évaluation des performances de configurations non conventionnelles utilisant des concepts de propulsion innovants. Le cas d'utilisation à considérer est l'optimisation au niveau conceptuel d'une aile volante à propulsion électrique distribuée, un concept prometteur combinant des performances aérodynamiques élevées et les avantages de la propulsion électrique.Le processus d'optimisation qui se base sur FAST, l'outil de dimensionnement avion ISAE-SUPAERO/ONERA, a été mis en œuvre dans OpenMDAO, l’environnement d’analyse et d’optimisation multidisciplinaire Open Source de la NASA. Avec l'idée d'une complexité croissante de l'analyse de conception multidisciplinaire et d'une meilleure identification des différents effets, les deux éléments innovants ont été étudiés séparément. Premièrement, le processus classique a été révisé pour tenir compte des systèmes de propulsion hybride. Deuxièmement, une méthode a été appliquée pour estimer le dimensionnement d’une cellule avion radicalement innovante. Enfin, un processus de conception intégrant ces deux aspects inédits a été mis au point pour étudier un concept d’aile volante à propulsion électrique distribuée.En ce qui concerne le processus de conception, les résultats montrent que l’utilisation de gradients dans la procédure d’optimisation réduit les temps de calcul par rapport à une méthode sans gradient d’environ 70\. Ce gain en temps est un avantage important au niveau du processus avant-projet qui facilite les tâches du concepteur. Pour les performances au niveau avion, les résultats ont été comparés à ceux obtenus pour un avion de type A320 classique, fondés sur les mêmes exigences de haut niveau et le même horizon technologique. Globalement, le concept de propulsion électrique hybride est intéressant car il permet des opérations à proximité du sol (atterrissage, décollage) sans émission et d’économiser du carburant pour les missions situées en dessous d’une certaine distance franchissable. Cette limitation est associée à la présence de batteries : elles introduisent en effet une pénalité de masse significative qui ne peut être annulée par les avantages de l'électrification pour de longues distances. Des simulations supplémentaires indiquent qu'un concept d’aile volante fondé sur une architecture uniquement turbo-électrique consomme toujours moins de carburant que l’avion de référence dans les limites des hypothèses prises en compte

Exploration du dimensionnement et priorités d'optimisation dans la conception avion avec application à une aile volante avec propulsion électrique distribuée

L’augmentation du trafic aérien au cours des dernières décennies et ses prévisions constituent un défi majeur pour arriver à une croissance neutre en carbone. Pour atteindre cet objectif sociétal, il est nécessaire de définir, en rupture avec les configurations actuelles, des concepts d’avion de transport intégrant de nouvelles technologies avec au final un impact minimal sur l’environnement. Ces futurs véhicules aériens reposent entre autres sur diverses interactions entre systèmes, disciplines et composants. Aussi, ces travaux de recherche se focalisent sur le développement d’une méthodologie dédiée à l’exploration et à l’évaluation des performances de configurations non conventionnelles utilisant des concepts de propulsion innovants. Le cas d’utilisation à considérer est l’optimisation au niveau conceptuel d’une aile volante à propulsion électrique distribuée, un concept prometteur combinant des performances aérodynamiques élevées et les avantages de la propulsion électrique.Le processus d’optimisation qui se base sur FAST, l’outil de dimensionnement avionISAE-SUPAERO/ONERA, a été mis en oeuvre dans OpenMDAO, l’environnement d’analyse et d’optimisation multidisciplinaire Open Source de la NASA. Avec l’idée d’une complexité croissante de l’analyse de conception multidisciplinaire et d’une meilleure identification des différents effets, les deux éléments innovants ont été étudiés séparément. Premièrement, le processus classique a été révisé pour tenir compte des systèmes de propulsion hybride. Deuxièmement, une méthode a été appliquée pour estimer le dimensionnement d’une cellule avion radicalement innovante. Enfin, un processus de conception intégrant ces deux aspects inédits a été mis au point pour étudier un concept d’aile volante à propulsion électrique distribuée.En ce qui concerne le processus de conception, les résultats montrent que l’utilisation de gradients dans la procédure d’optimisation réduit les temps de calcul par rapport à une méthode sans gradient d’environ 70%. Ce gain en temps est un avantage important au niveau du processus avant-projet qui facilite les tâches du concepteur. Pour les performances au niveau avion, les résultats ont été comparés à ceux obtenus pour un avion de type A320 classique, fondés sur les mêmes exigences de haut niveau et le même horizon technologique. Globalement, le concept de propulsion électrique hybride est intéressant car il permet des opérations à proximité du sol (atterrissage, décollage) sans émission et d’économiser du carburant pour les missions situées en dessous d’une certaine distance franchissable. Cette limitation est associée à la présence de batteries : elles introduisent en effet une pénalité de masse significative qui ne peut être annulée par les avantages de l’électrification pour de longues distances. Des simulations supplémentaires indiquent qu’un concept d’aile volante fondé sur une architecture uniquement turbo-électrique consomme toujours moins de carburant que l’avion de référence dans les limites des hypothèses prises en compte.The increase of air traffic in the last decades and its projections pose akey challenge towards the carbon neutral growth objective. To cope with this societal goal,there is a need for disruptive air transport aircraft concepts featuring new technologies withlow environmental impact. Such future air vehicle relies on the various interactions betweensystems, disciplines and components. This Ph.D. research thus focuses on the developmentof a methodology dedicated to the exploration and performance evaluation of unconventionalconfigurations using innovative propulsion concepts. The use case to be considered is the optimisationat conceptual level of a Blended Wing-Body with distributed electric propulsion, apromising concept which combines high aerodynamic performances and benefits from electricpropulsion.The optimisation process based on FAST, the ISAE-SUPAERO / ONERA aircraft sizingtool, has been implemented within OpenMDAO, the NASA open-source multidisciplinaryanalysis and optimisation framework. With the idea of a progressive enhancement of themultidisciplinary design analysis and a better capture of the different effects, the two pioneeringelements have been studied separately. First, the classical process has been revisedto take into account the new hybrid powerplant. Second, a methodology has been revisedto consider a radically new airframe design. Last, a design process featuring both innovativeaspects has been developed to investigate a Blended Wing Body concept with distributedelectric propulsion.Concerning the design process, results show that the use of gradients in the optimisationprocedure speeds up the process against a gradient-free method up to 70%. This is an importantgain in time that facilitates designer’s tasks. For the disruptive concept performances,results have been compared to the ones obtained for a conventional A320 type aircraft basedon the same top level requirements and technological horizon. Overall, the hybrid electricpropulsion concept is interesting as it allows zero emissions for Landing/Take-Off operations,improving the environmental footprint of the aircraft: fuel can be saved for missions below acertain range. This limitation is associated to the presence of batteries: indeed they introduceindeed a relevant penalty in weight that cannot be countered by benefits of electrification forlonger range. Additional simulations indicate that a Blended Wing-Body concept based on aturbo-electric only architecture is constantly performing better than the baseline within thelimits of the assumptions

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 has to be considered. One of the most promising concepts 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 Neo type aircraft, Entry Into Service 2035) is studied, considering different disciplines into the sizing process. The design loop has been reviewed to consider the unconventional concept. 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 demonstrates a gain in fuel consumption, especially on longer ranges

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

International audienceIn 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 apromising 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. Toevaluate 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

Unicentric localization of Castleman’s disease treated with laparoscopic and traditional approach. Report of two cases

Castleman’s disease (CD) is a rare lymphoproliferative disorder. Clinically CD has been subdivided in two forms: unicentric and multicentric. The unicentric type is limited to a single anatomic lymph-node-bearing region. The present report describes two cases of unicentric CD: the first was an abdominal localization treated with a laparoscopic approach; the second was a submaxillary localization treated with a classical approach. In case 1 the laparoscopic approach permitted to reach diagnosis, not clear after diagnostic imaging procedures, and enabled a total and excellent resolution of the patology because our patient,after eight months of follow up, has had no evidence of recurrence of the disease. In case 2 we want to highlight that CD should be considered in the differential diagnosis of a solitary neck mass and that the surgical treatment is diagnostic and curative at the same time