bluuebunny/crossref_metadata_2025_split huggingface dataset:
Study of fine structures for the two-phase flow control in the PEMFC channel
Authors: Gao Qian , Yuan Shu , Zuo Tao , Hou Junbo 
Published: February 2022

Abstract
The flow field design is an important approach to improve water management in exchange membrane fuel cells (PEMFCs), so it has always been a hot topic of research. We find that adding fine structures in the channel can change the two-phase flow behavior, which may improve the distribution of liquid water and promote water removal. In our research, four types of fine structures in the channel are investigated: continuous grooves, continuous bosses, intermittent grooves and intermittent bosses. The results show that the continuous grooves guide the water flow along the sidewall and the intermittent grooves create a disturbance to the airflow. Accordingly, liquid water has a faster discharge rate in the channel with continuous grooves and a more uniform distribution in the channel with intermittent grooves, which contribute to the water management in the channel. The boss structures should be avoided because they occupy much flow space and the liquid water near the bosses is difficult to remove. This work provides a new idea of channel design and confirms the effectiveness of the fine structure in water management. In the future, we will conduct further research on the shape and size of fine structures to achieve greater improvements in the water management capabilities of the flow channel.
Developing a new transportation container for irradiation source
Authors: Zhuang Dajie , Li Guoqiang , Wang Renze , Sun Hongchao , Liu Hongyan 
Published: February 2022

Abstract
China Institute for Radiation Protection (CIRP) was commissioned the work of developing FCTC10 container. FCTC10 container is designed to transport 60Co special form radioactive sources used in irradiation industry. With a loading of 6.7×1015 Bq, the package is a Type B(U). The dynamic finite element analyses were performed. The structural integrity of the transport package was evaluated considering the hypothetical accident condition conditions include 9 m free drop on rigid surface (drop I). we considered several candidate drop postures, including top over-the-corner drop, side drop and top drop, which are known to cause the most severe damages to the packages of cylindrical shape in most cases. It is shown that the posture of top over-the-corner for 9 m free drop is the most damaging posture, and the posture is chosen as the best experiment program in the following physical experiment of real package. And also the simulation results of deformation of a whole or a part of the package play a guiding role in the optimal design and experiment of container.
A review about microwave regeneration technology of waste activated carbon
Authors: Yang Dong , Du Xin 
Published: February 2022

Abstract
Activated carbon (AC) can concentrate and transfer pollutants using its own adsorption capacity. Waste AC is a kind of solid waste, its adsorption capacity of pollutants is greatly reduced after adsorption saturation. If handled improperly, it will cause secondary pollution to the environment. Therefore, it is necessary to regenerate the waste AC to restore its adsorption performance and reduce environmental pollution and resource waste. Microwave regeneration technology is of great research value because of its low energy consumption, time saving and high efficiency. Based on the characteristics of microwave heating and regeneration mechanism, this paper summarizes the advantages of microwave regeneration compared with conventional heating regeneration, and the application status of microwave technology in the regeneration of waste AC was reviewed. The influence of different types of pollutants adsorbed by AC, the change of control conditions for microwave regeneration of AC and the characteristics of AC itself on microwave regeneration were briefly described. And the development direction of microwave regeneration of AC in the future is also prospected.
Safety verification tests of low and intermediate level radioactive solid waste drum
Authors: Sun Shutang , Hong Zhe , Zhuang Dajie , Sun Hongchao , Yan Feng , Wang Xuexin , Chen Lei 
Published: February 2022

Abstract
Steel drums or boxes are used to transport, store, and dispose of low- and intermediate-level waste. According to relevant standards, before the solid waste container design is finalized, a series of type tests should be performed, including leakage test, water spray test, stacking test, penetration test, free-drop test, etc. This article focuses on the acceptance test and test methods for the LID- II b type waste drum finalization test. The tests in accordance with the standard requirements are the first time reported in China. It found the inherent design defects, and had high guiding significance to improve design and test verification operation.
Benchmark of different aerodynamic solvers on wing aero-propulsive interactions
Authors: Ciliberti Danilo , Benard Emmanuel , Nicolosi Fabrizio 
Published: February 2022

AbstractDistributed electric propulsion is a fertile research topic aiming to increase the wing aerodynamic efficiency by distributing the thrust over the wing span. The blowing due to distributed propulsors shall increase the wing lift coefficient for a given planform area and flight speed. This should bring several advantages as wing area, drag, and structural weight reduction, which in turn reduce fuel consumption, allowing airplanes to fly more efficiently. However, there are no consolidated preliminary design methods to size a distributed propulsion system. Numerical analysis is then performed at early stage, where many design variables have not been fixed yet. Therefore, the design space is vast and exploring all the possible combinations is unfeasible. For instance, low-fidelity methods (VLM, panel codes) have a low computational time, but usually they do not account for flow separation and hence they are unable to predict the wing maximum lift. Conversely, high-fidelity codes (CFD) provide more realistic results, but a single drag polar sweep can last days. This work provides a benchmark of different aerodynamic solvers for a typical regional turboprop wing with flaps and distributed propulsion, to better understand the limits of each software in the prediction of aero-propulsive effects.
Design challenges of cryogenic regional turboprop aerodynamic layout
Authors: Chernavskih Yu N , Chernousov V I , Krutov A A , Perchenkov E S , Pigusov E A 
Published: February 2022

Abstract
This paper is discussed the results of study on aerodynamic layout of the cryogenic regional turboprop with a low level of environmental impact. The use of cryogenic fuel (liquid hydrogen, liquefied natural gas) in aircraft will radically reduce harmful emissions into the atmosphere, as well as reduce fuel consumption. But the introduction of cryogenic fuel on transport category aircraft requires solving the problems of its storage on board. A modification of a regional twin-engine turboprop for operation on cryogenic fuel is considered. The problems and features of the placement of the fuel tank for cryogenic fuel are shown. The results of experimental studies of the aerodynamics of an aircraft model with a cryogenic tank and the results of the calculation of flight performance with various types of fuel are presented.
Dynamic sector characterisation model with the application of machine learning techniques
Authors: Pérez Moreno F , Gómez Comendador V F , Jurado R Delgado-Aguilera , Suárez M Zamarreño , Janisch D , Arnaldo Valdés R M 
Published: February 2022

Abstract
The ATC service has the objective of controlling airspace operations safely and efficiently. This control is becoming more and more difficult due to the increasing complexity of airspace. With the objective of collaborating and facilitating the provision of the control service, FLUJOS project aims to develop a methodology to characterise ATC sectors according to their complexity. This paper shows the first results obtained in this project. A methodology is proposed that first performs a statistical analysis of the data present in the flight plans of individual aircraft. The statistical analysis will be used to estimate the impact of air traffic flows. With this, the complexity of ATC sectors will finally be determined. In addition, a machine learning tool will be added to develop a dynamic methodology. After evaluating the methodology with data from Spanish airspace in 2019, it can be said that the results obtained are logical from an operational point of view, and that they allow a fairly accurate classification of the sectors based on their complexity. However, the proposed methodology is still a preliminary version, so more work will have to be done to add variables to achieve the objective of obtaining an even more accurate and realistic classification.
Machine Learning classification techniques applied to static air traffic conflict detection
Authors: Pérez-Castán Javier A. , Pérez-Sanz L. , Bowen-Varela J. , Serrano-Mira L. , Radisic Tomislav , Feuerle Thomas 
Published: February 2022

Abstract
This article evaluates Machine Learning (ML) classification techniques applied to air-traffic conflict detection. The methodology develops a static approach in which the conflict prediction is performed when an aircraft pierces into the airspace. Conflict detection does not evaluate separation infringements but a Situation of Interest (SI). An aircraft pair constitutes a SI when it is expected to get with a horizontal separation between both aircraft closer than 10 Nautical Miles (NM) and a vertical separation closer than 1000 feet (ft). Therefore, the ML predictor classifies aircraft pairs between SI or No SI pairs. Air traffic information is extracted from The OpenSky Network that provides ADS-B trajectories. ADS-B trajectories do not offer enough SI samples to be evaluated. Hence, the authors performed simulations varying the entry time of the trajectories to the airspace within the same time period. The methodology was applied to a portion of Switzerland airspace, and simulations reached a 5% rate of SI samples. Cost-sensitive techniques were used to handle the strong imbalance of the database. Two experiments were performed: the Pure model considered the whole database, and the Hybrid model considered aircraft pairs that intersect horizontally closer than 20 NM and vertically lower than 1000 ft. The Hybrid model provided the best results achieving 72% recall, representing the success rate of Missed alerts and 82% accuracy, which means the whole predictions’ success rate.
Implementation of genetic algorithms for supersonic airfoil optimization
Authors: Michelotti A , Cavini A , Giacopino R , Misino F , Piottoli L 
Published: February 2022

Abstract
This paper describes the exploitation of Genetic Algorithms for the selection and optimization of supersonic airfoils. The main objective of the optimization is to ensure the possibility to reach the maximum efficiency at a given lift coefficient. The surrogate model presented in this paper implements the shock-expansion theory, and the optimization problem is constrained with respect to three design variables, since Bézier curves are used for the parameterization of the Diamond-Shaped and the 40-elements Double Circular Arc airfoil geometries. The airfoils were optimized for three different Mach numbers and two different lift coefficients. A thickness-constrained optimization has been run to evaluate the possibility to obtain a specific lift coefficient at a given Mach number and to understand how this parameter influences the optimized airfoil shape performance in terms of efficiency and the range of feasible angles-of-attack. An off-design evaluation is also presented, allowing for a comparison of the optimized geometries in terms of versatility. High fidelity models were validated with RAE 2822 airfoil using STAR CCM+, and they were compared to the surrogated model to ensure higher quality in the results. In conclusion, the Genetics Algorithms optimization coupled with the shock-expansion theory model results to be a fast and valuable solution to select and optimize airfoil solutions. The application of this approach has shown that a 20% reduction in airfoil thickness leads to a 25% efficiency improvement, while widening the range of viable angles of attack.
Reduction of the environmental impact of aviation via optimisation of aircraft size/range and flight network
Authors: Rötger T , Casas G , Çelikel A , Dörries H , Lim L , Owen B , van Velzen A , Linke F , Lührs B , Lutz M , Radhakrishnan K 
Published: February 2022

Abstract
REIVON is a Clean Sky 2 Technology Evaluator project that investigates to what extent CO2 emissions of global aviation can be reduced via optimisation of aircraft size/range and flight network. Three alternative global flight networks are created, considering (1) splitting long-haul flights into shorter legs (intermediate stop operations, ISO), (2) reducing frequency to the necessary minimum on busy routes using larger aircraft, and (3) a combination of 1 and 2. In all cases, the use of aircraft optimised for specific combinations of range and seating capacity not existing today will be considered. For the first time, REIVON will carry out a holistic analysis of the impact of an optimised flight network on global air transport system stakeholders, such as passengers, aircraft manufacturers, airlines and airports, and of potential measures to support the implementation of such an alternative network.
Far-field pressure measurements of elliptic jets discharged close to a wing
Authors: Proença A. R. , Lawrence J. L. T. 
Published: February 2022

Abstract
This paper presents a preliminary experimental investigation into the acoustics of two elliptical jet nozzles installed close to a wing model. Acoustic pressure data is obtained for a range of observer polar angles mounted in the far field of the jets. Three nominal jet Mach numbers, namely 0.4, 0.6 and 0.8 are studied. Results suggest that the elliptic jets surveyed provide a noise reduction of the jet-surface installation noise source. The noise reduction is maximum in the forward arc and in the order of 1 dB for the fully-corrected overall sound pressure level data. Additionally, the noise benefit exists only when the minor axis of the elliptical nozzle is mounted parallel to the wing trailing edge. It is hypothesised that the reduction in the jet plume cross-section width limits the scattering of the near pressure field by the wing trailing edge to a lower frequency range. The jet mixing noise source, however, is seen to increase with decreasing nozzle exit-plane aspect ratio. The three jet velocities surveyed suggest the consistency of the key results discussed in the paper. Investigation of the jet turbulent flow structures and jet near pressure field is under way.
Performance evaluation of jet fuel production by hydrothermal liquefaction in Europe
Authors: Penke C , Özal G , Bellot F , Moser L , Batteiger V 
Published: February 2022

Abstract
The EU Horizon 2020 project HyFlexFuel successfully demonstrated hydrothermal liquefaction (HTL) fuel production chains from different feedstock types to upgraded kerosene products. Now the question arises which commercial scale HTL system design is associated with the lowest environmental impact and production costs. The contribution addresses this research question by establishing a comprehensive process model for different feedstock types (sewage sludge, straw, miscanthus and microalgae) based on experimental biocrude production and upgrading campaigns in pilot and laboratory scale. This model enables evaluating different process configurations and serves as basis for subsequent system analyses by applying techno-economic and life cycle analyses (TEA and LCA). Upgraded biocrude using sewage sludge, representing a waste stream in wastewater management, can be produced at near-competitive price levels. Compared to conventional jet fuel production, greenhouse gases are reduced significantly. However, sewage sludge is a limited resource and only limited amounts of jet fuel could be substituted. Lignocellulosic feedstock such as straw or miscanthus are available in larger quantities and provide the opportunity to produce large amounts of sustainable aviation fuels at moderate costs.
Application of Probabilistic principles to Set-Based Design for the optimisation of a hybrid-electric propulsion system
Authors: Spinelli Andrea , Anderson Luchien , Enalou Hossein Balaghi , Zaghari Bahareh , Kipouros Timoleon , Laskaridis Panagiotis 
Published: February 2022

AbstractCurrent research in hybrid-electric aircraft propulsion has outlined the increased complexity in design when compared with traditional propulsion. However, current design methodologies rely on aircraft-level analysis and do not include the consideration of the impact of new technologies and their uncertainty. This can be a key factor for the development of future hybrid-electric propulsion systems. In this paper, we present a methodology for exploring the design space using the principles of Set-Based Design, which incorporates probabilistic assessment of requirements and multidisciplinary optimisation with uncertainty. The framework can explore every design parameter combination using a provided performance model of the system under design and evaluate the probability of satisfying a minimum required figure of merit. This process allows to quickly discard configurations incapable of meeting the goals of the optimiser. A multidisciplinary optimiser then is used to obtain the best points in each surviving configuration, together with their uncertainty. This information is used to discard undesirable configurations and build a set of Pareto optimal solutions. We demonstrate an early implementation of the framework for the design of a parallel hybrid-electric propulsion system for a regional aircraft of 50 seats. We achieve a considerable reduction to the required function evaluations and optimisation run time by avoiding the ineffective areas of the design space but at the same time maintaining the optimality potential of the selected sets of design solutions.
Design of near-zero emission aircraft based on refined aerodynamic model and structural analysis
Authors: Memmolo V , Orefice F , Nicolosi F , Ricci F. 
Published: February 2022

Abstract
During recent years, aircraft manufacturers focused their attention on environmentally friendly and aerodynamically efficient aircraft concepts that could allow a radical reduction of emissions. The use of hybrid-electric powertrain is one of the most effective ways to design near-zero emission aircraft. These aircraft are highly performing and sophisticated. Hence, the design process must be extremely accurate and should make use of multidisciplinary design optimization. It is indeed crucial to establish both aerodynamic and structural models to simulate the aircraft performance and design required according to top level aircraft requirements. Despite the largely discussed literature about preliminary design of such an unconventional aircraft, there is still a lack of reliable weight estimation approaches, simulation-based mission analysis and optimization tools. In order to step towards higher technological readiness levels, the purpose of this paper is to describe and apply a design platform for conventional, turboelectric, hybrid-electric and full-electric aircraft, integrating aero-propulsive interactions, accurate power system modelling and medium-fidelity structural weight estimation. In particular, the comprehensive structural analysis of the aircraft wing opportunely designed according to certification specification and equipped with different powertrain architectures shows that it is worth looking into structural dynamics from preliminary design to estimate aircraft weight properly. Meanwhile, the mission analysis reveals performance benefits by implementing distributed engines all over the wingspan.
First Principle Model of an Electric ECS Pack
Authors: Eschenbacher P W , Zimmer D , Weber N 
Published: February 2022

Abstract
Fully electric environmental control systems for aircraft are designed but currently rarely implemented. Simulation models of such systems in the early design phase have shown a lot of challenges: high electric power demand, complex architecture, difficult design of control strategies and difficult sizing.
In order to explore what performance figures are physically possible, a first principle model has been developed on the basis of purely thermodynamic considerations. Similar to a Carnot thermal engine, which tells what efficiency is reachable, the first principle model of an ECS can serve as a reference system which tells the minimum amount of electric power needed to fulfil the thermal requirements. Different to a specific technical design, this allows for more general conclusions.
Ballistic impact response of reinforced honeycomb sandwich panels
Authors: Rayhan Saiaf Bin , Chowdhury Mahtab Uddin , Pu Xue 
Published: February 2022

Abstract
Honeycomb sandwich panels are extensively adopted in a wide range of structures including aircraft, ships, automobiles, and infrastructure for being lightweight and occupying high out-of-plane compression and out-of-plane shear properties. They are evenly popular for their attractive energy absorption capability and resistance to ballistic impacts. Reinforcement of the hexagonal honeycomb panels is an efficient way to improve the impact resistance. However, a detailed study on the reinforcement types against ballistic impacts has not yet been reported. Therefore, the current research investigates the improvement of total energy absorption, ballistic limit velocity, and specific energy absorption (SEA) of three different reinforced hexagonal honeycombs, namely, triangular, circular, and hexagonal reinforcements against high-velocity blunt impacts. A parallel study is also carried out without any reinforcement and only thickening the cell wall of the non-reinforced hexagonal honeycomb panel. A numerical approach is adopted with commercial finite element code Ansys Explicit to analyze the virtual impact cases. The plate of the honeycomb panel is assumed as aluminum alloy Al-7075-T6, while the honeycomb core is made of Al-5083-H116. For both the alloy variants, Johnson-Cook flow stress parameters are utilized. For the projectile, a blunt cylindrical-shaped structural steel bullet is considered. It is found that, for the current investigations, triangular and circular reinforcements can significantly improve the overall ballistic performance of the sandwich panels with a penalty of weight increment. However, thickening the cell wall of the hexagonal core without any reinforcement exhibits the best ballistic performance.