bluuebunny/crossref_metadata_2025 huggingface dataset:
Frequency modulation control strategy based on index calculation and energy storage system SOC
Authors: Wang Zhongyan , Song Yang , Li Ke , Si Ruicai , Wang Chenbo
Published: February 2022

With the increasing requirements for FM quality in power systems, more and more high-quality FM resources are participating in the FM auxiliary service market. This paper proposes a SOC control strategy based on index calculation and considering AGC power unit performance evaluation criteria. This strategy defines control strategies such as charging and discharging during idle time to keep the energy storage system SOC at 55%.This control method was first applied in a 10MW/5.6MW·h project of a power plant in Guangzhou. The application effect of the project shows that the control strategy has strong practicability and good application effect. Compared with other strategies, this control strategy increases the performance of the energy storage system by 3 to 4 times and greatly improves the economic benefits of the power plant.
Study on the effect of oligomer silicone surfactant on the properties of drilling fluids
Authors: Zhang Jie , Li Long , Xie Nanxing , Yao Xuyang , Zhao Zhiliang
Published: February 2022

Due to small hole roar, most of low-permeability gas reservoirs are water wetting, and the capillary effect is very prominent, resulting in water blocking damage in the process of exploitation for natural gas. A new kind of oligomer silicone surfactant (OSSF) was developed, and the physical and chemical properties of oligomer silicone surfactant were evaluated. The experimental results indicated that the critical micelle concentration of OSSF was 0.418×10-3 mol/L, and the critical surface tension of OSSF was 20.631 mN/m. OSSF could be adsorbed directionally at the water-rock pore interface, and the cores adsorbed with OSSF should reverse from water wetting to oil wetting or gas wetting. OSSF had good compatibility with sulphonated polymer mud. OSSF could play an important role in unlocking water blocking damage to increase production and efficiency.
Simulation study on the influence of different thermal insulation materials on the thermal environment of shallow underground space
Authors: Pan Zhen , Jiang Zhaocai , Wang Haoxu , Zhang Wenjie , Huang Fengcheng , Zhao Yingbo
Published: February 2022

In the shallow frozen soil in severe cold areas, the overall thermal performance of the structure is very important for the creation of the internal thermal environment. In this paper, CFD simulation calculation software is used to analyze the internal temperature field distribution of the shallow buried underground space with ordinary thermal insulation structure using only polyurethane and three improved thermal insulation structures with rock wool, polystyrene board and aerogel added. The results show that the three improved thermal insulation structures have an average increase of 9°C, 10.5°C and 12.5°C in indoor temperature compared with ordinary thermal insulation structures. Among them, thermal insulation materials in the form of polyurethane + air + aerogel have the most obvious improvement to the indoor environment.
Analysis of the difference between China Classifications for Petroleum Resources/Reserves 2020, SPE-PRMS 2018 and a China oil company’s overseas oil reserves standard
Authors: Xia Mingjun , Hu Yong
Published: February 2022

China oil company’s overseas petroleum assets and reserves belong not only to the company itself, but also to resource countries or joint venture companies. The adoption of reserves classification standards needs to meet the needs of different levels and resources / assets management. China Classifications for Petroleum Resources/Reserves (CCPR) divides reserves into three classes: geological, technical recoverable and commercial recoverable reserves, with three categories of proved, probable and possible reserves. The object of CCPR management is the physical volume of petroleum, with geological reserves as the focus of evaluation, and the deterministic method is mainly used for reserves evaluation. Society of Petroleum Engineers - Petroleum Resources Management System (SPE-PRMS) divides the remaining recoverable reserves into reserves and contingent resources based on commercial and sub-commercial. The terms low/best/high forecasts are used to estimate 1P/2P/3P quantities. It takes petroleum assets as the evaluation object, and the determination of evaluation parameters focuses on commercial recoverable reserves and value evaluation. In China oil company’s overseas oil reserves standard (company standard), geological reserves and recoverable reserves are clearly divided into P and C classes, which are subdivided into P1\P2\P3 and C1\C2\C3 categories. It takes oil reservoirs, traps, wells and company assets as the evaluation object. It not only emphasizes the commercial opportunities, development feasibility, and uncertainty, but also emphasizes the resources attributes of geological reserves, geological characteristics, reservoir parameters, and production performance. When China oil company acquires overseas petroleum resources, geological reserves need to be included in the national reserves statistics to serve the national energy security strategy, resource management and development planning. CCPR need to be adopted; When conducting assets transactions, communicating with resource countries and joint venture partners, SPE-PRMS need to be adopted; When conducting company exploration and development, operation, preparation of development plans, etc., company standard need to be adopted. The adoption of the three reserves standards can generally take into account the needs of the international, national, and company levels, as well as the management of petroleum resources and assets.
Hydro-mechanical coupling numerical simulation method of multi-scale pores and fractures in tight reservoir
Authors: Liu Lifeng , Xiao Yuxiang , Wu Zhongbao , Wang Xin
Published: February 2022

In the fracturing, injection and production of unconventional tight reservoirs, the change of fluid pressure will cause significant changes in effective stress, which will greatly affect the dynamic characteristics of the reservoir. On the basis of the adaptive seepage numerical simulation method for different scale medium of tight oil in the early stage, through the study of the deformation mechanism and deformation law of natural / artificial fractures and matrix pores during the whole life cycle including hydraulic fracturing, production and fluid injection to supplement energy, the dynamic variation models of multi medium geometry, physical properties, conductivity and well index are established, and the multi medium fluid solid coupling dynamic simulation technology is formed. The integrated dynamic simulation of multi-media complex seepage and hydro-mechanical coupling is realized.
Responses of evapotranspiration to changing climate for the past six decades in the upper catchment of the Olifants River basin
Authors: Nkhonjera German K. , Dinka Megersa O. , Woyessa Yali E.
Published: February 2022

In river basins such as the Olifants, the evapotranspiration has been documented as the biggest water user and therefore one of the most important hydrological processes in the basin. Thus, using the Soil and Water Assessment Tool (SWAT) model, this study attempted to assess the hydrological responses of evapotranspiration (ET) to climate change in the Olifants River basin over a period of six decades, focusing mainly on the upper catchment (UC) of the basin. The study showed, on average, a general decline of seasonal ET with a decrease of 10.5% in spring, 29.8% in summer and 17.3% in winter. However, autumn ET showed an average increase of 12.5%. With (1960 – 1970) decade considered as the baseline, the study also found that annual ET in the UC, has been on the decline consistently since the 1960s with the most recent decade (2010 – 2018) taking the biggest share of the drop (12.8%). Here, the average annual decline of ET of 1.75 mm/yr was observed with most of the decline happening in the last decade. This general decadal trend of annual ET mortality in the area coincides with the temperature rise and precipitation decrease of the area, signifying the impact climate change may have had on the evapotranspiration for the past six decades.
Research on the green transition of heavy chemical enterprises in Jiangsu Province
Authors: Jiang Jun , Chen Jing
Published: February 2022

By carrying out the green transition and upgrading of heavy chemical industry in Jiangsu, it is conducive to improving the industrial competitiveness and the level of clean production of key industries; it is conducive to establishing the system and mechanism of ecological priority and green development of the Yangtze River economic belt, and promoting high-quality development. Based on the development practice of heavy chemical industry in Jiangsu Province, this study analyzes its negative effects on the high-quality development of the Yangtze River economic belt. This paper puts forward the index of green transition of industry, establishes the measurement and evaluation model of green transition of heavy chemical industry in Jiangsu Province. Based on the empirical research results, this paper puts forward the green transition path of Jiangsu heavy chemical industry.
Effects of pH on sex organ differentiation and sexual reproduction in the endangered aquatic fern Ceratopteris p teridoides
Authors: Dong Yuanhuo , Liao Kuo , Zeng Changli , Xu Guoquan , Dia Xigang
Published: February 2022

Ceratopteris pteridoides is an endangered aquatic floating fern in China. The effects of different pH values on spore germination, sex organ differentiation in C. pteridoides are studied by a control experiment of setting pH gradients of 4, 5, 5.5, 6, 6.3, 6.5, 7, 7.5, 8, 9 in this paper. The results show that spore germination rates (26.1% and 19.30%, respectively) in pH = 4 and pH = 9 are significantly lower (P<0.05) than in reference group (45.63%, pH = 6.3), indicating that spore germination in C. pteridoides is adaptable over a wide range of pH. The optimum pH for spore germination, sex organ differentiation, and gametophyte development in C. pteridoides is between 6 and 7. An ANOVA of the different pH values after cultivation showed that hermaphrodite gametophyte emergence rates in 4, 5, 7.5, 8, 9 pH values were significantly lower (P<0.05) than those of the reference group. This may pose a threat to the sexual reproduction of the wild population of Ceratopteris pteridoides .
Consideration of river governance based on the concept of urban spatial resilience
Authors: Chen Feng , Yuan Wenqi , Wang Li , Ding Jie , Li Chengling , Wang Bo
Published: February 2022

The reasonable scale of urban river ecological space and the connectivity of bank and slope water and soil exchange are the basic conditions to keep the flow of matter, energy and species in water unimpeded, as well as the way out for the dilemma of urban river ecological governance. The concept of resilience in spatial planning is used to break the artificial partition between river land space and water space, explore the compound function of urban space, and realize the way of integration and synergism of land and water space.The research shows that scientific overall planning and rational utilization of urban space is the basis of realizing land function combination and solving urban river governance predicament. Urban spatial planning and layout should highlight the backbone role of river-dominated urban eco-environment texture, restore the function of river network ecological corridor, build the integration of public open space and river space, optimize the use of land resources for achieving functional compounding; Meanwhile, expand the three-dimensional space of the river, increase the spatial diversity, improve the openness of the waterfront space for achieving functional balance through collaboration. To break the artificial boundaries of waters and land areas and form the integration of land and water area, the water environment management of river spatial design needs to focus on key elements such as the urban river network plane shape, the spatial layout of river sections, the ecological treatment and reconstruction of bank protection, and the temporal and spatial evolution of rivers. Application of multi-natural river ecological restoration, near-natural river construction, semi-natural ecological flood control and other technologies can achieve the ecological treatment effect of bank protection and improve the ecological permeability of bank slope. By opening up the river space, it provides a limited dynamic change space for the river bed and a space that evolves with time, which is conducive to exerting the function of ecological corridor of urban river system and driving the improvement and promotion of ecological environment in urban areas.
Experimental study on instantaneous plume characteristics based on flame 3D reconstruction
Authors: Lu Ziping , Wang Dong , Jiang Nan , Cao Bei , Yang Lizhong , Zhang Yuyang , Zhai Chunjie
Published: February 2022

3D flame can directly represent the combustion status of combustible and fire scale, but flame pulsation makes it difficult for existing 3D reconstruction technology to achieve flame reconstruction. In response to this situation, we use computer image processing technology to propose a flame model based on the cylindrical hypothesis to realize the 3D reconstruction of the flame in this paper. On this basis, we measured the volume and height of flames with different fuel flow rates for 6 types of burners. The results show that the average flame height and volume increase with the increase of fuel flow rate, but the average flame height decreases with the increase of the burner size, and there is no obvious correlation between the average volume and burner size.
Research on coal moisture analysis model based on near infrared spectroscopy
Authors: Zhou Yiyou , Zheng Quanjun , Hu Xiaoying , Liang Hui , Dong Changqing
Published: February 2022

In order to make full use of the advantages of rapid and non-destructive measurement of coal moisture by near-infrared spectroscopy, the 29 original coal samples in the experiment were artificially humidified, and the moisture content of each coal sample was controlled within a different interval of 0-40%; diffuse reflectance near-infrared spectra were collected on the coal samples. The sample was selected according to the random method, Kennard-Stone (KS) method, and Rank-KS method for the selection of calibration set and prediction set. The prediction models of coal moisture content were established by multiple linear regression (MLR) and partial least squares algorithm (PLS) combined with different spectral pretreatment methods, furthermore, water modeling based on BP neural network was established according to optimal sample classification. The results show that when Rank-KS algorithm was used to select correction set and prediction set, the prediction ability of water content prediction model can be significantly improved by using either MLR or PLS, and the root mean square error of prediction (RMSEP) can be minimized; the moisture prediction model of the BP neural network algorithm based on the full-spectrum feature information is the best, the RMSEP value is the smallest among all models, and the model has the best prediction ability.
Ideal radiation parameters of energy-saving coatings for exterior wall
Authors: Yao Hongxin , Yi Yang , Wang Xiyao , Ye Hong
Published: February 2022

Optimizing the solar absorptivity (α) and thermal emissivity (ε) of coatings for the exterior wall is an effective way to reduce building energy consumption (BEC). Guangzhou, Hefei and Beijing are chosen as the representative cities of the hot, hot-summer and cold-winter, and cold regions respectively, and the effects of α and ε of the exterior surface of the wall on the BECs of the residential buildings are studied. It is found that the BEC is much more sensitive to α than to ε, especially in summer, which means that solar irradiation is the main factor affecting the BEC. The optimal combination for Guangzhou, Hefei, and Beijing are (α=0 & ε=1), (α=0 & ε=0), and (α=1 & ε=0) respectively. The energy-saving performances of the six existing exterior wall coatings are evaluated, and the results show that the energy-saving performances of the coatings still need to be improved. Taking the most energy-efficient one in the six coatings as an example, the energy-saving potentials of coatings for Guangzhou, Hefei and Beijing are approximately 11%, 2% and 4% respectively.
The screening of high-efficiency ammonia-nitrogen degrading bacteria and their influencing factors were studied
Authors: Huang Xu , Chen Wenlong , Cai Mingxuan , Hei Liang
Published: February 2022

By enriching the culture medium, three dominant bacteria(X1, X2 and X3) were selected from the farmland sludge. The degradation effect of X1, X2, X3 and mixed bacterium(X123) under different initial ammonia nitrogen(NH3-N) concentration, pH and C/N were studied under laboratory, the effect of X123 was compared with purchased bacteria(S1, S2 and S3) and strains in published literature. The results showed that X123 had the best effect when the initial NH3-N concentration was 20 mg·L−1, pH was 7 and C/N was 10, the degradation rate was 96.4% after 2 days of culture. Comparing X123 with S1, S2 and S3, it was found that X123 had the best effect. Comparing X123 with the strains in published literature, it can be seen that the difference for the degradation of NH3-N was very small, and the growth conditions of the strain were almost same. It was shown that X123 can effectively degrade NH3-N from wastewater, which has potential of application for treatment of nitrogen polluted wastewater.
Research on prefabricate-decoration integration technology based on prefabricated bathroom
Authors: Cheng Caishu , Gao Ruofan , Xu Guangti , Liu Jiaqi , Ran Kailin
Published: February 2022

According to the 14th Five-year Plan proposed in China, the development of green buildings is one of the most important measures to accelerate the promotion of green and low-carbon development. Prefabricated buildings have been widely promoted and applied in furnished apartments because of the high construction efficiency, energy saving and emission reduction. In order to solve the problem of the storey height wasting of the furnished apartment and the reasonable application of energy saving, this paper puts forward a new prefabricate-decoration integration technology based on the prefabricated bathroom, and realizes an integrated design of the components produced in the factory. The two-story structure on the basis of prefabricated bathroom is assembled in the form of furniture.
Review on mechanism and technical measures of urban rainwater harvesting
Authors: Zhang Dongqing , Ding Xiangyi , Liu Jiahong , Mei Chao
Published: February 2022

The urban water problem has become one of the most significant problems hindering sustainable urban development. Rainwater harvesting and utilization is a green solution to alleviate the urban water problem. However, existing urban rainwater management pays more attention to flood control and lacks systematic planning for rainwater harvesting in China. In this paper, the calculation methods of rainwater harvesting potential are investigated, and the difference of rainwater harvesting system between the traditional model and sponge model is compared based on the rainwater harvesting mechanism. In addition, the study progress of four representative rainwater harvesting measures (green roofs, bioretention ponds, infiltration wells, and rainwater tanks) is reviewed and four representative optimization tools are listed. Moreover, we summarized the challenge of rainwater harvesting and provided recommendations for future research on the rainwater harvesting system. This review aims to provide theoretical support for the comprehensive utilization of urban rainwater resources to promote the sustainable development of cities.
Development of innovative technologies for manufacturing of certified narrow body aircraft composite flap
Authors: Alberotanza D. , Pinto F. , Polo S. , Zaccaria G. , Capoccello D.
Published: February 2022

Fiber-reinforced polymer composites perfectly meet the basic requirements of aircraft flaps being weight reduction critical for fuel saving and increased payload. New technologies have been designed and developed to increase competitiveness in the use of composite materials by ensuring a continuous manufacturing process, a streamlined and balanced flow of activities, synchronized as much as possible with customer and market demand, reducing material scraps and non-value-added activities.

Resin excess, tool mark-offs, out of tolerance dimensions are potential defects generated during the hand lay-up process of the skin manufacturing of composite flap.

Innovative technologies for manufacturing of certified narrow body aircraft composite flaps have been designed and developed in order to achieve the best quality of the product and the program ramp-up.

Detailed tooling analysis and several simulations, included process flow and bottlenecks detection, have been performed in order to design the new process with high level of automation and reliable devices for human safety and production repeatability, that fully meets the customer’s expectations.
Preliminary design of a BWB UAV for highway traffic monitoring
Authors: Dimitriou S , Kapsalis S , Dimopoulos T , Mitridis D , Pouchias K , Panagiotou P , Yakinthos K
Published: February 2022

The current work presents the preliminary design procedure of a small-scale, fixed-wing Unmanned Aerial Vehicle (UAV), incorporating the novel Blended-Wing-Body (BWB) layout configuration. The UAV is designed to support a Cooperative-Intelligent Transport System (C-ITS), for monitoring traffic conditions at large national highways. The presented UAV design procedure emphasizes on both aerodynamic and stability behavior, aiming to a high aerodynamic efficiency and the satisfaction of the mission requirements. The design is supported by CFD analyses, to determine the aerodynamic and stability coefficients. Following the CFD modeling, the performance parameters of the platform are calculated. Furthermore, an internal layout study is conducted to integrate all the necessary internal components, determining the center of gravity. Finally, the overall UAV design concludes to an optimum configuration of the UAV-ITS, satisfying all the aerodynamic, stability and mission requirements.
Analysis of vulnerability of ATM to weather phenomena
Authors: Vito Vittorio Di , Bucchignani Edoardo , Montaquila Roberto Valentino , Cerasuolo Giovanni , Montesarchio Myriam , Zollo Alessandra Lucia , Cinquegrana Davide
Published: February 2022

Weather conditions and Air Traffic Management (ATM) operations are strongly related, due to the relevant influence that the observed and forecasted weather conditions into assigned airspace have on the operational conditions that are therefore possible for such airspace. In the framework of the SESAR JU funded project CREATE (Innovative operations and climate and weather models to improve ATM resilience and reduce impacts), therefore, a dedicated study has been carried out in order to investigate the relation between weather and ATM. Such study both investigated the consequences that adverse weather conditions can have on ATM and, on the other side, addressed the currently and future available tools that can support ATM in the prediction and management of weather conditions from the aeronautical operations point of view. In this paper, the results of such literature study are outlined. More in details, in the paper first the main outcomes of the study are summarized, in terms of identification of the most relevant weather phenomena that affect the ATM operations, indication of their main impacts on them in terms of operational disruptions and, finally, identification of the associated level of severity. In particular, the above indicated aspects are addressed by taking into specific consideration the enroute and the TMA (Terminal Manoeuvring Area) flight phases and, for each of them, the main affecting weather phenomena and the main affected operations are identified. Then, in the paper the results of the study are summarized about the identification of the most relevant meteo tools that are expressed by state-of-the-art technologies to support the ATM operations in order to properly take into account the weather conditions in a precise and timely manner. This study addresses both the review of available and perspective tools for weather reporting and of the available and perspective numerical models supporting ATM in terms of weather models and air quality models.
Safety Performance Functions to predict Separation Minima Infringements in en-route airspace
Authors: Jurado R Delgado-Aguilera , Gómez Comendador V F , Zamarreño Suárez M , Pérez Moreno F , Verdonk Gallego C E , Arnaldo Valdés R M
Published: February 2022

The objective of this methodology is to characterise the safety of air routes under a systematic framework, in terms of Separation Minimum Infringements (SMI) between en-route aircraft based on models known as Safety Performance Functions (SPF). Bayesian Networks have been selected as techniques with high predictive capability and low probability event estimation. Moreover, they allow the integration of knowledge modelling with data inference. It is complex to develop a Bayesian Network model for SMI prediction. It is necessary to integrate the available knowledge about the precursors of SMIs together with the accumulated knowledge from the analysis of the collected data into a conceptual framework. This framework underpinning the Bayesian Network model focuses on the Closest Point of Approach (CPA) analysis and considers the general scenario of aircraft evolution in an air traffic sector. In order to translate this conceptual framework into a set of causal sub-networks, the ATM barrier and event tree models are used.
Conceptual design of a fixed wing hybrid UAV UUV platform
Authors: Papadopoulos C , Vlachos S , Yakinthos K
Published: February 2022

In this work, the conceptual design methodology of a hybrid Unmanned Aerial Vehicle (UAV) – Unmanned Underwater Vehicle (UUV) platform is presented. As the mission complexity and the need for interoperability between different platforms grows more demanding by the day, hybrid platforms are becoming an essential solution. Hybrid UAV-UUVs can operate seamlessly and repeatedly in both the aerial and underwater environments, something that numerous animal species already execute in an optimized way. The design methodology starts with the review of the few available prototypes, creating initial design trends and continues with analytical calculations. These calculations are based on aircraft design textbooks and are modified to take into account the special characteristics of a hybrid platform, such as the means of transition between the water and the air. A Blended Wing Body (BWB) layout configuration is selected for the numerous aerodynamic advantages that it offers. The analytical calculations are then validated with the use of high fidelity CFD calculations. The results from the conceptual design phase indicate that the proposed methodology for hybrid UAV-UUV configurations provides a good design accuracy. Finally, the outcome of this methodology, which is a hybrid UAV-UUV platform is potentially the answer to the operational gap for missions that include both underwater and aerial environments.
Development of plasma actuators for re-ignition of aeroengine under high altitude conditions
Authors: Mehdi Ghazanfar , Sara Bonuso , Maria Grazia De surname
Published: February 2022

Re-ignition of aeroengine under high altitude conditions is of great importance to the safety and use of lean-burn engines. The present work investigated the experimental and numerical analysis of flow and re-ignition characteristics in a rectangular burner. A ring-needle type plasma actuator was developed and powered by high voltage nanopulsed plasma generator with different percentage values of amplitude voltage and frequencies. Flow visualizations by using high speed camera and Proper Orthogonal Decomposition (POD) were performed to recognize the dominant flow structures. Experimental results showed the transport effects such as induced flow with an impact on the recirculation zone near the corners of combustor, improving the mixing performance, which could be contribute to the reduction of ignition delay timings. Experimental characterization in non-reactive flow allowed the estimation of the electrical power and the optimal reduced electric field (EN) value, which was then used as input to the numerical study for the flame ignition analysis. Ignition characteristics were analyzed by coupling two different numerical tools ZDPlasKin and Chemkin. It was noticed that time required to achieve the maximum flame temperature with plasma actuation is significantly reduced in compared with autoignition timings (clean case). Maximum reduction in ignition timings was observed at inlet pressure 1 bar (3.5×10-5 s) in respect to clean case (1.1×10-3 s). However, as the inlet pressure is reduced, the ignition delay timings were increased. At 0.6 bar flame ignition was occurred at 0.0048s and 0.0022s and in clean case and plasma actuation case, respectively.
Analysis of working fluids applicable for high-temperature loop heat pipe applications
Authors: Gakal P , Mishkinis D , Leilands A , Usakovs I , Orlov R , Rogoviy Y
Published: February 2022

An objective of this study was to perform an analysis of available working fluids and select those one(s) that will be able to comply with the specific requirements of the ultra-high bypass ratio (UHBR) engine air bleed system and ensure efficient LHP operation. A multi-step approach was applied to analyse more than 700 working fluids and select four potential candidates, taking into account (1) working fluids compliance with EU regulations; (2) working fluids freezing, boiling, and critical points for the operating temperature range; (3) working fluids specific properties that influence the LHP performances. Selected fluids (toluene, acetone, methanol, 1,2-dichlorobenzene) were subjected to accelerated life tests to check their chemical compatibility with AISI 316 stainless steel to be used as the LHP material. Based on the results obtained, the toluene was selected as the working fluid for application in the innovative LHP-based thermal management solution for the UHBR engine air bleed system.
Ventilation Analysis of Simplified Engine Nacelle for Pusher Aircraft
Authors: Olejnik A. , Kiszkowiak L. , Dziubmski A.
Published: February 2022

The paper contains the results of CFD analysis of flow inside the simplified engine nacelle, containing the engine in a pusher configuration. The authors have tested a set of solutions to increase an efficiency of the cooling system of this type of engine. Unfortunately, all the positive effects of the fact, that the aircraft engine appears in the wake of the propeller during taxiing and waiting for takeoff, are nonexistent in this type of configuration. An engine overheating is here a problem, because an airflow has to be pulled through the nacelle to cool down the engine block and radiators of cylinder heads. That design demands to analyze the cover shape of the nacelle, to properly use the main propeller pressure jump on the one hand, and rather adequate and complicated flow inside the nacelle to be modelled on the other. The aircraft CAD geometry has been simplified to allow for simple changes of the nacelle cover shape and easily introducing new inlets and outlets. The results prove, that the proper application of scoops gives even better result, than simply removing the cover and baffles from the engine. The exhaust scoops should be placed near the propeller plane in such pusher configuration, because the engine is not covered by the propeller wake.
Automatic tool-based pre-processing of generic structural models for water impact simulations in the aircraft pre-design
Authors: Leon Muñoz C , Petsch M , Kohlgrüber D , Pedelaborde-Augas M
Published: February 2022

The integration of automated tool capabilities for the generation of models for transient dynamic calculations in the scope of the aircraft pre-design is described in this paper. The Python-based DLR framework PANDORA, initially developed for the modelling and the sizing of aircraft structures in multidisciplinary process chains, is considered for this work. The focus lays on the generation of suitable numerical models for the water impact simulation. To enable this, the internal tool database was extended to consider additional features such as contact definitions, mesh-free formulations, enhanced connection models and specific control options. The generation of the CPACS-based FE aircraft model was extended by means of discretisation and additional structural components. The generation of the water domain was also included according to user defined inputs like pool dimensions, initial conditions and the selection of an appropriate fluid modelling approach. In addition, a feature to launch a simulation directly within the framework was included. Finally, options to retrieve and visualize results from finished water impact simulations were also integrated, allowing to display contour and time history plots.
Regional jet retrofitting through multidisciplinary aircraft design
Authors: Mandorino Massimo , Vecchia Pierluigi Della , Nicolosi Fabrizio , Cerino Giovanni
Published: February 2022

Multidisciplinary collaborative aircraft design is applied to a 90 passengers regional jet aircraft retrofit, highlighting the impact on costs and performance. Two retrofitting packages have been considered: the re-engining of conventional power-plant platform with advanced geared turbofan and the on-board-system modernization, considering different level of electrification. Starting from a reference existing aircraft, the impact of retrofitting process has been carefully evaluated on capital costs and savings at industrial level through a developed methodology. At aircraft level, masses, performance, noise, and emissions have been computed with dedicated competences increasing the estimation reliability. Overall process is implemented in the framework of the AGILE 4.0 research project in a collaborative remote multidisciplinary approach. Results show that such retrofitting activities are expensive and must be evaluated since the design stage with a bottom-up approach requiring competences coming from designer experience to correctly define the process work-breakdown-structure and its implications.
Investigation of the impact of a particle foam insulation on frost buildup on the aircraft structure
Authors: Norrefeldt Victor , Riedl Gerhard
Published: February 2022

The aircraft insulation separates the thermally comfortable cabin interior environment from the extremely cold outside condition. However, the fabrication and installation of the insulation in the aircraft is a labour intensive task. Tailored, rigid particle foam parts could be a solution to speed up installation process. The presented study investigates the feasibility of such a concept from a hygrothermal point of view. Due to the temperature difference between the cold air trapped between aircraft skin and insulation on one side and the warm cabin air on the other side, a buoyancy induced pressure difference forms. This effect drives the warmer air through leakages in the insulation system towards the cold skin. Here, moisture contained in the air condenses on the cold surfaces, increasing the risk for uncontrolled dripping (“rain in the plane”) when it melts. Therefore, this study compares the frost build-up of different installations of a rigid particle foam frame insulation with the classical glass fiber capstrip. Tests are hosted in the Fraunhofer Lining and Insulation Test Environment chamber.
A motorized and remotely controlled Horizontal Tailplane for efficient WT testing
Authors: Berger Matthias , Flamini Luca , Pasta Roberto , Servadio Cesare , Adden Stephan , Seiler Jendrik , Flamini Luciano , Paletta Nicola
Published: February 2022

The H2020-Cleansky 2 project EULOSAM II supports the development and assessment of an innovative natural laminar aircraft wing by integrating innovative aerodynamic control surfaces and high lift technologies. The project focuses on the modification and completion of a WT-model to enable robust and efficient testing. EULOSAM II is a project funded by the EC through the Clean Sky 2 JU and carried out in cooperation with Dassault Aviation. In order to ensure efficient testing a key element of EULOSAM II was to develop and validate a solution to improve the WT test productivity, which was achieved by designing, manufacturing and testing a remotely controlled, actuated HTP which significantly reduces the time needed in the WT for model-configuration changes. The model under review is a business jet half-model, test will be performed in the ONERA F1 Wind Tunnel, at high Reynolds numbers and low Mach Numbers typical of high-lift conditions. This paper presents the outcome of the whole development process of the actuated solution. This development includes the mechanical design as well as the control-solution to be applied in the WT. Pre-Tests have been performed in order to show that the implemented solution is working well and is robust enough to enable smooth and productive testing operations. In this paper, details on the design as well as explanations on why specific solutions were down-selected and found to be most effective ones are presented. During the final development phase, to investigate the functionality and robustness of the system, ground tests have been conducted with the assembled model on test benches to save WT time and to enable faster troubleshooting. Actuating WT models are seen as key to increase WT test efficiency, therefore this is in particular interesting for WT-test which have high hourly test-costs. Lessons learned for future applications therefore will be given to discuss if solutions found so far can be extrapolated to other, comparable applications.
Analysis of the application of fuselage skin reinforcements with beam element representations in flexible full aircraft models for ditching simulations
Authors: Leon Muñoz C , Kohlgrüber D , Langrand B
Published: February 2022

The aim of this paper is the application of beam element representations for structural skin reinforcements in flexible full aircraft FE models used in ditching simulations. To verify this approach, it was initially analyzed on flexible reinforced bottom-aircraft panels under guided ditching conditions, considering also structural mesh size variations and partly corresponding fluid mesh densities. For this analysis two different numerical methods were used for comparisons, the coupled Finite Element-Smoothed Particle Hydrodynamics and the Arbitrary Lagrangian Eulerian methods. For the generation of the full aircraft model a multidisciplinary process chain approach and a standardized data format description are used. The beam element representations are considered for the modelling of skin reinforcement as well as other structures like cabin and cargo floor structures. By this approach, first time feasible full aircraft ditching simulations and the subsequent analysis of both global kinematics and the local fuselage structural response could be achieved.
System architectures for thermal management of hybrid-electric aircraft - FutPrInt50
Authors: Affonso Walter , Tavares RenataT. , Barbosa Felipe R. , Gandolfi Ricardo , dos Reis Ricardo J. N. , da Silva Carlos R. I. , Kipouros Timoleon , Laskaridis Panagiotis , Enalou Hossein Balaghi , Chekin Andrei , Kukovinets Aleksey , Gubernatorov Konstantin , Ravikovich Yury , Ivanov Nikolay , Ponyaev Leonid , Holobtsev Dmitry
Published: February 2022

Electric and Hybrid-Electric Aircraft (HEA) propulsion system designs shall bring challenges at aircraft and systems level, mainly in propulsion, electric and thermal management systems (TMS). The electrification of the propulsion system relies on large and high-power electrical equipment (e.g., electrical motors, converters, power electronics, batteries, and others) that dissipate heat at a rate at least one order of magnitude higher than conventional propulsion aircraft systems. As a result, high impacts on weight, drag and power consumption of the TMS/cooling systems at the aircraft level are expected. This paper proposes potential technologies to perform the thermal management of future electric and HEA, in the context of FUTPRINT50 project. For each technology, relevant aspects such as its integration to aircraft, safety, operational and maintenance impacts, certification, technologies readiness level (TRL) and the latest research works are analysed. A quantitative comparison of the several technologies is also proposed considering weight, volume, electric power consumption, pneumatic air flow and cooling air flow per cooling effect. Lastly, we present a set of potential TMS architectures for HEA.
Hybrid-electric and hydrogen powertrain modelling for airplane performance analysis and sizing
Authors: Khan YM , Rolando A , Salucci F , Riboldi CED , Trainelli L
Published: February 2022

This paper describes a framework for parametric modelling of hybrid-electric powertrain components for innovative airplane configurations. These models are used in scalability studies and performance analysis of novel propulsion architecture. The methodology involves culmination of these models in a set of tools specifically developed to study the initial and conceptual sizing of hybrid-electric aircraft. This allows quick parametric evaluation of various configurations based on components at different technology readiness levels, such as batteries and fuel cells. Characteristics and performance of the power-train components are evaluated using computational analysis as well as laboratory tests. This information is used to develop numerical models described in the paper and to validate the sizing of fundamental propulsion components. Applications to two variants of a commuter aircraft are given, one using a serial hybrid-electric architecture based on a thermal engine, and the other using a fuel-cell system fed by a gaseous hydrogen tank.
Intrinsic interfaces between additively manufactured metal and composite structures for use in electric propulsion engines
Authors: Pohl M. , Spitzer S. , Grothe R. , Weidermann Ch. , Gude M.
Published: February 2022

For electric aviation drive systems engines with significantly increased power density are required. Combining the technologies of additive manufacturing of metals with the technologies of fiber reinforced composites enables hybrid structures with same or increased functionality and lower mass. Rotors or housings in hybrid design have interfaces to adjacent structures are classically made of metal. Areas for remote load transmission or with increasing distance to the rotation axis can be made of carbon fiber reinforced plastic (CFRP). The interfaces between these two materials, required for such a hybrid metal-CFRP design, can be specifically designed by using the design options of additive manufacturing to fulfill the required functions with a the most even distribution of stress possible. However, the large number of degrees of freedom of the material and the geometry leads to great challenges for engineers in the development of such structures. Within the scope of this publication, an approach for the function-oriented design of a metal-CFRP rotor for an aviation electric motor is proposed (global design). A design and pre-dimensioning method for the intrinsic interface between the materials is presented (local design).
Influence Of Polymer Coating Thickness On Damage Tolerance And Residual Strength Of Composite Material
Authors: Kudryavtsev O A , Leshkov E V , Olivenko N A , Ignatova A V , Bezmelnitsyn A V
Published: February 2022

The low impact resistance of laminated polymer composites is a significant problem. Even barely visible impact damages can significantly decrease the residual strength of the composite. In this article, the effect of the thickness of a polymer coating based on hollow glass microspheres on the damage tolerance and residual strength of glass fibre-reinforced plastic (GFRP) was studied. 4 mm thick GFRP specimens with polymer coatings of different thicknesses were prepared. The thickness of the coatings varied from 0.4 mm to 1.2 mm. The specimens were tested on a vertical drop tower system with impact energies up to 25 J. The dimensions of the obtained defects were determined using infrared thermography. The residual strength of the specimens was determined using the Flexure-After-Impact protocol. It was found that the 1 mm thick coating with a surface density of 650 g/m2 made it possible to reduce the damaged area by 35% and to increase the residual flexural strength of the GFRP specimens by 27% in comparison with the uncoated ones.
Cost Optimized Avionics System – Navigation Solution for Small Aircraft Transportation Segment
Authors: Vaispacher Tomas , Sotak Milos , Kana Zdenek , Baranek Radek , Malinak Pavol , Kucera Matej
Published: February 2022

Modern navigation systems represent an inherent part of avionic equipment onboard all aircraft categories. The standard navigation performance typically defined by accuracy, integrity, availability, and continuity is now complemented by the system’s ability to reduce CO2 emissions and fuel consumption. This article describes current navigation system development executed by Honeywell International for SAT (Small Aircraft Transportation) segment defined by CS-MMEL ATA 34 Navigation. The proposed solution is based on INS/GNSS hybridization extended by other aiding sensors available onboard the aircraft. To create a technological solution that meets the system operational requirements of the segment and at the same time comply with SWAP-C (Size, Weight, And Power Consumption Related to Cost) requirements is the aim of this research activity. The article describes proposed integration architecture based on hybridized core and other aiding sensors, such as radar altimeter and magnetometer. The assessment of previously mentioned aiding sensors was performed and impact on navigation performance was determined. The emphasis was mainly put on Inertial Measurement Unit (IMU) meeting the low-cost requirement for the overall architecture. The IMU error model definition and long-term thermal chamber measurements are the main tools for understanding the stochastic behaviour of the IMU’s. The accuracy improvement is further supported by implementing SBAS corrections in INS/GNSS hybridization. This is not a usual navigation solution for SAT segment, since, typically, standalone GNSS receiver with SBAS is used instead. The Monte Carlo simulations were performed to compare the performance of the proposed solution against system and operational requirements. A proprietary Honeywell tool for these large-scale simulations is capable to simulate the navigation exercise anywhere on the Earth using pre-defined trajectories with specific duration and simulated GNSS constellation to reflect the impact of the satellite geometry.