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An Aircraft Icing Detection Method Based on Performance Data of Rotor
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作者 WU Yuan ZHU Dongyu +1 位作者 XU Lingsong YU Lei transactions of nanjing university of aeronautics and astronautics 2025年第2期212-225,共14页
Existing icing detection technologies face challenges when applied to small and medium-sized aircraft,especially electric vertical take-off and landing(eVTOL)aircraft that meet the needs of low-altitude economic devel... Existing icing detection technologies face challenges when applied to small and medium-sized aircraft,especially electric vertical take-off and landing(eVTOL)aircraft that meet the needs of low-altitude economic development.This study proposes a data-driven icing detection method based on rotor performance evolution.Through dry-air baseline tests and dynamic icing comparative experiments(wind speed 0—30 m/s,rotational speed 0—3000 r/min,collective pitch 0°—8°)of a 0.6 m rotor in the FL-61 icing wind tunnel,a multi-source heterogeneous dataset containing motion parameters,aerodynamic parameters,and icing state identifiers is constructed.An innovative signal processing architecture combining adaptive Kalman filtering and moving average cascading is adopted.And a comparative study is conducted on the performance of support vector machine(SVM),multilayer perceptron(MLP),and random forest(RF)algorithms,achieving real-time identification of icing states in rotating components.Experimental results demonstrate that the method exhibits a minimum detection latency of 6.9 s and 96%overall accuracy in reserved test cases,featuring low-latency and low false-alarm,providing a sensor-free lightweight solution for light/vertical takeoff and landing aircraft. 展开更多
关键词 ROTOR PROPELLER aircraft icing icing detection machine learning support vector machine(SVM) multilayer perceptron(MLP)
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Transactions of Nanjing University of Aeronautics and Astronautics Information for Contributors
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transactions of nanjing university of aeronautics and astronautics 2025年第2期F0003-F0003,共1页
Transactions of Nanjing University of Aeronautics&Astronautics(TNUAA)is a bimonthly journal facing international academic community.Emphasizing prompt and effective dissemination of key data and new scientific ins... Transactions of Nanjing University of Aeronautics&Astronautics(TNUAA)is a bimonthly journal facing international academic community.Emphasizing prompt and effective dissemination of key data and new scientific insights,TNUAA publishes experimental and theoretical papers bearing on applications to all branches of aeronautics,astronautics and civil aviation. 展开更多
关键词 experimental papers AERONAUTICS ASTRONAUTICS civil aviation theoretical papers experimental theoretical papers
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Design and Ground Verification for Vision-Based Relative Navigation Systems of Microsatellites
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作者 DU Ronghua LIAO Wenhe ZHANG Xiang transactions of nanjing university of aeronautics and astronautics 2025年第1期37-55,共19页
This paper presents the design and ground verification for vision-based relative navigation systems of microsatellites,which offers a comprehensive hardware design solution and a robust experimental verification metho... This paper presents the design and ground verification for vision-based relative navigation systems of microsatellites,which offers a comprehensive hardware design solution and a robust experimental verification methodology for practical implementation of vision-based navigation technology on the microsatellite platform.Firstly,a low power consumption,light weight,and high performance vision-based relative navigation optical sensor is designed.Subsequently,a set of ground verification system is designed for the hardware-in-the-loop testing of the vision-based relative navigation systems.Finally,the designed vision-based relative navigation optical sensor and the proposed angles-only navigation algorithms are tested on the ground verification system.The results verify that the optical simulator after geometrical calibration can meet the requirements of the hardware-in-the-loop testing of vision-based relative navigation systems.Based on experimental results,the relative position accuracy of the angles-only navigation filter at terminal time is increased by 25.5%,and the relative speed accuracy is increased by 31.3% compared with those of optical simulator before geometrical calibration. 展开更多
关键词 microsatellites vision-based relative navigation optical simulator ground verification angles-only navigation
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Review on Multi-objective Dynamic Scheduling Methods for Flexible Job Shops and Application in Aviation Manufacturing
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作者 MA Yajie JIANG Bin +3 位作者 GUAN Li CHEN Lijun HUANG Binda CHEN Zhi transactions of nanjing university of aeronautics and astronautics 2025年第1期1-24,共24页
Intelligent production is an important development direction in intelligent manufacturing,with intelligent factories playing a crucial role in promoting intelligent production.Flexible job shops,as the main form of in... Intelligent production is an important development direction in intelligent manufacturing,with intelligent factories playing a crucial role in promoting intelligent production.Flexible job shops,as the main form of intelligent factories,constantly face dynamic disturbances during the production process,including machine failures and urgent orders.This paper discusses the basic models and research methods of job shop scheduling,emphasizing the important role of dynamic job shop scheduling and its response schemes in future research.A multi-objective flexible job shop dynamic scheduling mathematical model is established,highlighting its complex and multi-constraint characteristics under different interferences.A classification discussion is conducted on the dynamic response methods and optimization objectives under machine failures,emergency orders,fuzzy completion times,and mixed dynamic events.The development process of traditional scheduling rules and intelligent methods in dynamic scheduling are also analyzed.Finally,based on the current development status of job shop scheduling and the requirements of intelligent manufacturing,the future development trends of dynamic scheduling in flexible job shops are proposed. 展开更多
关键词 flexible job shop dynamic scheduling machine breakdown job insertion multi-objective optimization
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Optimization of High-Speed WIG Airfoil with Consideration of Non-ground Effect by a Two-Step Deep Learning Inverse Design Method
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作者 WANG Chenlu SUN Jianhong +4 位作者 ZHENG Daren SUN Zhi ZUO Si LIU Hao LI Pei transactions of nanjing university of aeronautics and astronautics 2025年第1期56-69,共14页
Under complex flight conditions,such as obstacle avoidance and extreme sea state,wing-in-ground(WIG)effect aircraft need to ascend to higher altitudes,resulting in the disappearance of the ground effect.A design of hi... Under complex flight conditions,such as obstacle avoidance and extreme sea state,wing-in-ground(WIG)effect aircraft need to ascend to higher altitudes,resulting in the disappearance of the ground effect.A design of high-speed WIG airfoil considering non-ground effect is carried out by a novel two-step inverse airfoil design method that combines conditional generative adversarial network(CGAN)and artificial neural network(ANN).The CGAN model is employed to generate a variety of airfoil designs that satisfy the desired lift-drag ratios in both ground effect and non-ground effect conditions.Subsequently,the ANN model is utilized to forecast aerodynamic parameters of the generated airfoils.The results indicate that the CGAN model contributes to a high accuracy rate for airfoil design and enables the creation of novel airfoil designs.Furthermore,it demonstrates high accuracy in predicting aerodynamic parameters of these airfoils due to the ANN model.This method eliminates the necessity for numerical simulations and experimental testing through the design procedure,showcasing notable efficiency.The analysis of airfoils generated by the CGAN model shows that airfoils exhibiting high lift-drag ratios under both flight conditions typically have cambers of among[0.08c,0.105c],with the positions of maximum camber occurring among[0.35c,0.5c]of the chord length,and the leading-edge radiuses of these airfoils primarily cluster among[0.008c,0.025c] 展开更多
关键词 conditional generative adversarial network(CGAN) artificial neural network(ANN) airfoil design wing-in-ground(WIG)aircraft ground effect
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A Structural Dynamic Response Reconstruction Method for Continuous System Based on Kalman Filter
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作者 LI Hongqiu JIANG Jinhui MOHAMED M Shadi transactions of nanjing university of aeronautics and astronautics 2025年第2期250-260,共11页
The structural dynamic response reconstruction technology can extract unmeasured information from limited measured data,significantly impacting vibration control,load identification,parameter identification,fault diag... The structural dynamic response reconstruction technology can extract unmeasured information from limited measured data,significantly impacting vibration control,load identification,parameter identification,fault diagnosis,and related fields.This paper proposes a dynamic response reconstruction method based on the Kalman filter,which simultaneously identifies external excitation and reconstructs dynamic responses at unmeasured positions.The weighted least squares method determines the load weighting matrix for excitation identification,while the minimum variance unbiased estimation determines the Kalman filter gain.The excitation prediction Kalman filter is constructed through time,excitation,and measurement updates.Subsequently,the response at the target point is reconstructed using the state vector,observation matrix,and excitation influence matrix obtained through the excitation prediction Kalman filter algorithm.An algorithm for reconstructing responses in continuous system using the excitation prediction Kalman filtering algorithm in modal space is derived.The proposed structural dynamic response reconstruction method evaluates the response reconstruction and the load identification performance under various load types and errors through simulation examples.Results demonstrate the accurate excitation identification under different load conditions and simultaneous reconstruction of target point responses,verifying the feasibility and reliability of the proposed method. 展开更多
关键词 dynamic load identification structural response reconstruction excitation identification Kalman filter continuous system
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Research on Transport and Mixing Dynamics of Valveless Piezoelectric Pump with Airfoil Baffles
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作者 XIONG Jian KUANG Ming +3 位作者 WANG Lu AFFANE Hiba HUANG Yadong HUANG Jun transactions of nanjing university of aeronautics and astronautics 2025年第2期238-249,共12页
To reduce the complexity of mixing systems and improve mixing efficiency,this paper proposes a valveless piezoelectric pump integrated with airfoil baffles,which embodies both active and passive mixing attributes.The ... To reduce the complexity of mixing systems and improve mixing efficiency,this paper proposes a valveless piezoelectric pump integrated with airfoil baffles,which embodies both active and passive mixing attributes.The airfoil baffles are designed using the asymmetric NACA63-412 profile.The impact of the airfoil angle of attack on the flow field within the tube and the output and mixing performance of the piezoelectric pump is investigated.Computational simulations of the tube with airfoil baffle indicated that as the angle of attack increases,the position of vortex generation at the leading and trailing edge regions of the airfoil baffle progressively moves forward in the direction of fluid flow.Then the vortex volume enlarges,and the vortex intensity within the flow field rises.Subsequently,the prototypes of valveless piezoelectric pumps at four different angles of attack are fabricated and their output performances are experimentally evaluated.The results demonstrate that the maximum output flow rate of the pump decreases with an increasing angle of attack.At an angle of attack of 0°,the maximum output flow rate of the pump reaches 225.3 ml/min.Mixing performance experiments are conducted using the piezoelectric pump for the synthesis of Fe_(3)O_(4)particles.The findings indicate that as the angle of attack increases,the number of Fe_(3)O_(4)particles formed in the mixture significantly rises,with a narrower particle size distribution and more regular morphology.At an angle of attack of 15°,the synthesized Fe_(3)O_(4)particles have an approximate diameter of 10μm.The outcomes of this paper offer valuable insights for the design of microfluidic systems,catering to the demands of material synthesis,chemistry,and biomedical applications. 展开更多
关键词 micro mixer airfoil baffle piezoelectric pump VORTEX Fe_(3)O_(4)particles
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Effects of Dynamics Behavior and Size Distribution of Supercooled Large Droplets on Ice Accretion Processes
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作者 ZHANG Dexin ZENG Tenghui +5 位作者 WANG Liu SUN Bo CHENG Zikang FENG Jiaxin XIE Junlong CHEN Jianye transactions of nanjing university of aeronautics and astronautics 2025年第2期201-211,共11页
Accurate simulation of ice accretion of supercooled large droplet(SLD)is pivotal for the international airworthiness certification of large aircraft.Its complex dynamics behavior and broad particle size distributions ... Accurate simulation of ice accretion of supercooled large droplet(SLD)is pivotal for the international airworthiness certification of large aircraft.Its complex dynamics behavior and broad particle size distributions pose significant challenges to reliable CFD predictions.A numerical model of multi-particle SLD coupling breaking,bouncing and splashing behaviors is established to explore the relationship between dynamics behavior and particle size.The results show that the peak value of droplet collection efficiencyβdecreases due to splashing.The bounce phenomenon will make the impact limit S_(m)of the water drops decrease.With the increase of the SLD particle size,the water drop bounce point gradually moves toward the trailing edge of the wing.The critical breaking diameter of SLD at an airflow velocity of 50 m/s is approximately 100μm.When the SLD particle size increases,the height of the water droplet shelter zone on the upper edge of the wing gradually decreases,and the velocity in the Y direction decreases first and then increases in the opposite direction,increasing the probability of SLD hitting the wing again.Large particle droplets have a higher effect on the impact limit S_(m)than smaller droplets.Therefore,in the numerical simulation of the SLD operating conditions,it is very important to ensure the proportion of large particle size water droplets. 展开更多
关键词 supercooled large droplet(SLD) splash and bounce break up effect critical diameter particle size distribution
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Efficient Reconstruction of Spatial Features for Remote Sensing Image-Text Retrieval
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作者 ZHANG Weihang CHEN Jialiang +3 位作者 ZHANG Wenkai LI Xinming GAO Xin SUN Xian transactions of nanjing university of aeronautics and astronautics 2025年第1期101-111,共11页
Remote sensing cross-modal image-text retrieval(RSCIR)can flexibly and subjectively retrieve remote sensing images utilizing query text,which has received more researchers’attention recently.However,with the increasi... Remote sensing cross-modal image-text retrieval(RSCIR)can flexibly and subjectively retrieve remote sensing images utilizing query text,which has received more researchers’attention recently.However,with the increasing volume of visual-language pre-training model parameters,direct transfer learning consumes a substantial amount of computational and storage resources.Moreover,recently proposed parameter-efficient transfer learning methods mainly focus on the reconstruction of channel features,ignoring the spatial features which are vital for modeling key entity relationships.To address these issues,we design an efficient transfer learning framework for RSCIR,which is based on spatial feature efficient reconstruction(SPER).A concise and efficient spatial adapter is introduced to enhance the extraction of spatial relationships.The spatial adapter is able to spatially reconstruct the features in the backbone with few parameters while incorporating the prior information from the channel dimension.We conduct quantitative and qualitative experiments on two different commonly used RSCIR datasets.Compared with traditional methods,our approach achieves an improvement of 3%-11% in sumR metric.Compared with methods finetuning all parameters,our proposed method only trains less than 1% of the parameters,while maintaining an overall performance of about 96%. 展开更多
关键词 remote sensing cross-modal image-text retrieval(RSCIR) spatial features channel features contrastive learning parameter effective transfer learning
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Impingement Characteristics Investigation of Supercooled Large Droplets Based on Eulerian Method
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作者 YE Zekun SHEN Xiaobin +1 位作者 ZHAO Jingyu LIN Guiping transactions of nanjing university of aeronautics and astronautics 2025年第2期191-200,共10页
This numerical simulation investigates the two⁃phase flow under the condition of supercooled large droplets impinging on the aircraft surface.Based on Eulerian framework,a method for calculating supercooled water drop... This numerical simulation investigates the two⁃phase flow under the condition of supercooled large droplets impinging on the aircraft surface.Based on Eulerian framework,a method for calculating supercooled water droplet impingement characteristics is established.Then,considering the deformation and breaking effects during the movement,this method is extended to calculate the impingement characteristics of supercooled large droplets,as well as the bouncing and splashing effects during impingement.The impingement characteristics of supercooled large droplets is then investigated by this method.The results demonstrate that the deformation and breaking effects of supercooled large droplets have negligible influence on the impingement characteristics under the experimental conditions of this paper.In addition,the results of the impingement range and collection efficiency decrease when considering the bouncing and splashing effects.The bouncing effect mainly affects the mass loss near the impingement limits,while the splashing effect influences the result around the stagnation point.This investigation is beneficial for the analysis of aircraft icing and the design of anti⁃icing system with supercooled large droplet conditions. 展开更多
关键词 aircraft icing droplet impingement characteristics supercooled large droplet(SLD) Eulerian method numerical simulation
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Spray Icing Simulation and Anti⁃icing Optimization for Ship Intake Grilles in Cold Environments
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作者 FENG Huiying PAN Tao +1 位作者 LOU Yanxia BU Xueqin transactions of nanjing university of aeronautics and astronautics 2025年第2期226-237,共12页
This study addresses the issue of spray icing on the air intake grilles of ship power systems in cold maritime environments.Through numerical simulation methods,the influence of environmental parameters on icing chara... This study addresses the issue of spray icing on the air intake grilles of ship power systems in cold maritime environments.Through numerical simulation methods,the influence of environmental parameters on icing characteristics is revealed,and an energy-efficient zoned electric heating anti-icing strategy is proposed.A threedimensional grille model is constructed to systematically analyze the effects of environmental temperature(from−20℃to−4℃),droplet diameter(from 50μm to 500μm),and liquid water content(from 0.5 g/m³to 8 g/m³)on icing rates and blockage of the flow channel.The results indicate that low temperature and high liquid water content significantly exacerbate icing.Under the condition of an environmental temperature of−20℃,droplet diameter of 500μm,and liquid water content of 8 g/m³,the flow channel blockage ratio reaches 30.95%within 10 min.Additionally,as droplet diameter increases,the droplet impingement and icing regions become more concentrated toward the leading edge of blades.To mitigate grille icing in cold environments,an electric heating film configuration is employed for thermal protection.Optimization of the heating strategy reveals that the zoned heating approach,compared to the initial uniform heating scheme,effectively homogenizes surface temperature distribution while reducing total power consumption by 37.47%.This study validates the engineering applicability of the zoned electric heating anti/de-icing strategy,providing theoretical and technical support for the design of anti-icing systems in ship power systems operating in cold maritime regions. 展开更多
关键词 ship intake grilles icing characteristics maritime environment flow channel blockage zoned electric heating strategy
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On Advances of Diffuse⁃Interface Immersed Boundary Method and Its Applications
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作者 YANG Liming SHU Chang +2 位作者 DU Yinjie WU Jie WANG Yan transactions of nanjing university of aeronautics and astronautics 2025年第2期137-161,共25页
The diffuse-interface immersed boundary method(IBM)possesses excellent capabilities for simulating flows around complex geometries and moving boundaries.In this method,the flow field is solved on a fixed Cartesian mes... The diffuse-interface immersed boundary method(IBM)possesses excellent capabilities for simulating flows around complex geometries and moving boundaries.In this method,the flow field is solved on a fixed Cartesian mesh,while the solid boundary is discretized into a series of Lagrangian points immersed in the flow field.The boundary condition is implemented by introducing a force term into the momentum equation,and the interaction between the immersed boundary and the fluid domain is achieved via an interpolation process.Over the past decades,the diffuse-interface IBM has gained popularity and spawned many variants,effectively handling a wide range of flow problems from isothermal to thermal flows,from laminar to turbulent flows,and from complex geometries to fluidstructure interaction scenarios.This paper first outlines the basic principles of the diffuse-interface IBM,then highlights recent advancements achieved by the authors’research group,and finally shows the method’s excellent numerical performance and wide applicability through several case studies involving complex moving boundary problems. 展开更多
关键词 immersed boundary method diffuse-interface moving boundary incompressible flows turbulent flows
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Exponential Attitude-Orbit Coordinated Control for Gravitational-Wave Detection Spacecraft Formation with Large-Scale Communication Delays
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作者 XING Youpeng SONG Yinsheng +1 位作者 YIN Zeyang CHEN Xiaofang transactions of nanjing university of aeronautics and astronautics 2025年第1期70-79,共10页
This paper concerns the exponential attitude-orbit coordinated control problems for gravitational-wave detection formation spacecraft systems.Notably,the large-scale communication delays resulting from oversized inter... This paper concerns the exponential attitude-orbit coordinated control problems for gravitational-wave detection formation spacecraft systems.Notably,the large-scale communication delays resulting from oversized inter-satellite distance of space-based laser interferometers are first modeled.Subject to the delayed communication behaviors,a new delay-dependent attitude-orbit coordinated controller is designed.Moreover,by reconstructing the less conservative Lyapunov-Krasovskii functional and free-weight matrices,sufficient criteria are derived to ensure the exponential stability of the closed-loop relative translation and attitude error system.Finally,a simulation example is employed to illustrate the numerical validity of the proposed controller for in-orbit detection missions. 展开更多
关键词 gravitational-wave detection spacecraft formation attitude-orbit coordinated control large-scale communication delays exponential stability
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Extended Nested Array with a Filled Sensor for DOA Estimation of Non-circular Signals
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作者 LI Xiaolong ZHANG Xiaofei SHEN Zihan transactions of nanjing university of aeronautics and astronautics 2025年第1期90-100,共11页
Sparse array design has significant implications for improving the accuracy of direction of arrival(DOA)estimation of non-circular(NC)signals.We propose an extended nested array with a filled sensor(ENAFS)based on the... Sparse array design has significant implications for improving the accuracy of direction of arrival(DOA)estimation of non-circular(NC)signals.We propose an extended nested array with a filled sensor(ENAFS)based on the hole-filling strategy.Specifically,we first introduce the improved nested array(INA)and prove its properties.Subsequently,we extend the sum-difference coarray(SDCA)by adding an additional sensor to fill the holes.Thus the larger uniform degrees of freedom(uDOFs)and virtual array aperture(VAA)can be abtained,and the ENAFS is designed.Finally,the simulation results are given to verify the superiority of the proposed ENAFS in terms of DOF,mutual coupling and estimation performance. 展开更多
关键词 non-circular signal extended nested array sparse array direction of arrival(DOA)estimation sum-difference coarray
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An Electro⁃thermal De⁃icing Model and Simulation Analysis Considering Ice Shedding
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作者 ZHANG Yingying YUAN Xiansheng +1 位作者 XIONG Jingjiang BU Xueqin transactions of nanjing university of aeronautics and astronautics 2025年第2期162-177,共16页
The electro⁃thermal anti/de-icing systems have high heating efficiency and relatively simple structures,marking them as a key development direction for future icing protection.Existing simulation algorithms for electr... The electro⁃thermal anti/de-icing systems have high heating efficiency and relatively simple structures,marking them as a key development direction for future icing protection.Existing simulation algorithms for electrothermal de-icing seldom delve into comprehensive ice accretion-melting-deicing models that account for ice shedding.Therefore,the detachment behavior of ice layers during the heating process requires in-depth research and discussion.This paper physically models the phenomenon of ice shedding,incorporates the detachment behavior of ice layers during heating,improves the existing mathematical model for electro-thermal de-icing calculations,establishes an ice accretion-melting-deicing model for electro-thermal de-icing systems,and conducts numerical simulation,verification and optimization analysis of electro-thermal de-icing considering ice shedding.Through multi-condition de-icing numerical simulations of a specific wing model,it is found that ambient temperature can serve as a factor for adapting the electro heating anti/de-icing strategy to the environment.An optimization of heating heat flux density and heating/cooling time is conducted for the wing de-icing control law under the calculated conditions.The improved electrothermal de-icing model and algorithm developed in this paper provide solid technical support for the design of electrothermal de-icing systems. 展开更多
关键词 aircraft icing electro-thermal de-icing ice shedding electro-thermal control law numerical simulation
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Modeling and Mode Switching Analysis of Electro-hydrostatic Actuators for Primary Flight Control System
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作者 GUO Tuanhui FU Yongling CHEN Juan transactions of nanjing university of aeronautics and astronautics 2025年第1期25-36,共12页
With the advancement of more electric aircraft(MEA)technology,the application of electro-hydrostatic actuators(EHAs)in aircraft actuation systems has become increasingly prevalent.This paper focuses on the modeling an... With the advancement of more electric aircraft(MEA)technology,the application of electro-hydrostatic actuators(EHAs)in aircraft actuation systems has become increasingly prevalent.This paper focuses on the modeling and mode switching analysis of EHA used in the primary flight control actuation systems of large aircraft,addressing the challenges associated with mode switching.First,we analyze the functional architecture and operational characteristics of multi-mode EHA,and sumarize the operating modes and implementation methods.Based on the EHA system architecture,we then develop a theoretical mathematical model and a simulation model.Using the simulation model,we analyze the performance of the EHA during normal operation.Finally,the performance of the EHA during mode switching under various functional switching scenarios is investigated.The results indicate that the EHA meets the performance requirements in terms of accuracy,bandwidth,and load capacity.Additionally,the hydraulic cylinder operates smoothly during the EHA mode switching,and the response time for switching between different modes is less than the specified threshold.These findings validate the system performance of multi-mode EHA,which helps to improve the reliability of EHA and the safety of aircraft flight control systems. 展开更多
关键词 large aircraft flight control system electro-hydrostatic actuator(EHA) mode switching simulation analysis
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Icing Characteristics and Anti⁃icing Research of Supercooled Large Droplet Impact on Epoxy Composite Surfaces
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作者 LI Xiaofei WANG Xiangzhao +2 位作者 JI Zemin HUANG Xiaobin LIU Hong transactions of nanjing university of aeronautics and astronautics 2025年第2期178-190,共13页
The icing characteristics of supercooled large droplet(SLD)impacting carbon fiber-reinforced composites(CFRCs)remain poorly understood,hindering the enhancement of ice protection capabilities and the certification of ... The icing characteristics of supercooled large droplet(SLD)impacting carbon fiber-reinforced composites(CFRCs)remain poorly understood,hindering the enhancement of ice protection capabilities and the certification of ice-accreted composite aircraft.The paper systematically investigates the effects of the supercooling degree,the surface temperature,and the impact velocity on the ice accretion behavior of SLDs impacting carbon fiber-reinforced epoxy composite surfaces.To address the ice-prone nature of CFRCs,nanoparticle-modified anti-icing coatings are developed,and the icing characteristics of SLD-impacted modified carbon fiber-reinforced epoxy composite surfaces are analyzed.Results demonstrate that surface-modified carbon fiber-reinforced epoxy composite exhibits significantly delayed ice formation.Under conditions of droplet temperature(−15℃)and surface temperature(−18℃),the icing time of hydrophobic-modified CFRCs was delayed by over 1100 ms,representing a 5.4-fold improvement compared to the unmodified carbon fiber-reinforced epoxy composite. 展开更多
关键词 aircraft icing carbon fiber-reinforced epoxy composites supercooled large droplets hydrophobic modification icing protection
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Continuous Rapid-Beam-Scanning and Circular-Polarized Leaky⁃Wave Antenna Based on Meandering-SIW with Defected Ground Structures
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作者 RUAN Yizheng NIU Zhenyi +2 位作者 CHEN Weikang ZHAO Yongjiu PAN Shilong transactions of nanjing university of aeronautics and astronautics 2025年第1期80-89,共10页
A compact high-scanning-rate circular-polarized leaky-wave antenna(LWA)based on a meandering substrate integrated waveguide(SIW)with defected ground structures(DGSs)is presented.The meandering-SIW design is employed t... A compact high-scanning-rate circular-polarized leaky-wave antenna(LWA)based on a meandering substrate integrated waveguide(SIW)with defected ground structures(DGSs)is presented.The meandering-SIW design is employed to enhance the beam scanning rate,while circular polarization is achieved by etchingπ-shaped slots on the top plane.To suppress the open stopband at broadside,offset circular DGSs are periodically etched on the ground plane.Their impact on the reflection coefficient and axial ratio is then analyzed through a parametric study.A prototype of the antenna is simulated,fabricated,and measured.Both simulated and measured results indicate a scanning rate of approximately 8.6,with continuous beam scanning from-41°to 59°across the 11.3-12.7 GHz operating band.The antenna maintains an axial ratio below 3 dB within the 11.5-12.3 GHz range.This design shows promise for use in wireless communication systems,particularly in environments with increasingly limited spectrum resources. 展开更多
关键词 leaky-wave antenna(LWA) scanning rate circular polarization open stopband defected ground structure(DGS)
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Investigation on Processing Technology of Minimum Quantity Lubrication Nozzle and Its Influence on Atomization Effect
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作者 LI Donghui ZHANG Tao +1 位作者 ZHENG Tao QI Wei transactions of nanjing university of aeronautics and astronautics 2025年第2期261-274,共14页
Minimum quantity lubrication(MQL)is a technique that achieves effective lubrication and cooling of the cutting zone by using a minimal amount of cutting fluid.This results in a decrease in the cutting temperature,exte... Minimum quantity lubrication(MQL)is a technique that achieves effective lubrication and cooling of the cutting zone by using a minimal amount of cutting fluid.This results in a decrease in the cutting temperature,extending the cutting tool life and improving the surface quality of the workpiece.Optimizing the nozzle settings can enhance the cooling and lubrication performance of MQL,leading to increased processing efficiency and product quality.Nozzles with different shapes are fabricated,and different outlet diameters and wall thicknesses are set.The cutting process takes into account the impact of spindle speed and feed rate.An experimental study is conducted to investigate the atomization cone angle and particle size distribution of different nozzles.The circular nozzle is more conducive to the concentrated injection of an atomized liquid beam.The atomization cone angle is the largest when the nozzle outlet diameter is 1.2 mm.Enlarging the nozzle outlet diameter will increase the diameter of the atomized droplets.The atomization cone angle increases while the droplet diameter decreases with the increase of outlet wall thickness.Properly increasing the outlet wall thickness is beneficial to improving the atomization quality.The droplet diameter increases firstly and then decreases with the increase of spindle speed and feed rate.Increasing the MQL gas supply pressure and reducing the lubricating oil flow rate will improve the atomization quality of the nozzle.Studies on the influence of the MQL nozzle processing technology on the atomization effect can help to enhance the cooling and lubrication performance of the MQL technology,leading to improved processing efficiency and quality. 展开更多
关键词 minimum quantity lubrication(MQL) nozzle processing spray cone angle droplet diameter
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Trial-Manufacture and Experimental Study of Particle Damping Boring Bar for Deep Hole Boring of 7075 Aluminum Alloy
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作者 HUANG Yi HAN Jianxin DONG Qingyun transactions of nanjing university of aeronautics and astronautics 2025年第1期123-136,共14页
7075 aluminum alloy is often used as an important load-bearing structure in aircraft industry due to its superior mechanical properties.During the process of deep hole boring,the boring bar is prone to vibrate because... 7075 aluminum alloy is often used as an important load-bearing structure in aircraft industry due to its superior mechanical properties.During the process of deep hole boring,the boring bar is prone to vibrate because of its limited machining space,bad environment and large elongation induced low stiffness.To reduce vibration and improve machined surface quality,a particle damping boring bar,filled with particles in its inside damping block,is designed based on the theory of vibration control.The theoretical damping coefficient is determined,then the boring bar structure is designed and trial-manufactured.Experimental studies through impact testing show that cemented carbide particles with a diameter of 5 mm and a filling rate of 70% achieve a damping ratio of 19.386%,providing excellent vibration reduction capabilities,which may reduce the possibility of boring vibration.Then,experiments are setup to investigate its vibration reduction performance during deep hole boring of 7075 aluminum alloy.To observe more obviously,severe working conditions are adopted and carried out to acquire the time domain vibration signal of the head of the boring bar and the surface morphologies and roughness values of the workpieces.By comparing different experimental results,it is found that the designed boring bar could reduce the maximum vibration amplitude by up to 81.01% and the surface roughness value by up to 47.09% compared with the ordinary boring bar in two sets of experiments,proving that the designed boring bar can effectively reduce vibration.This study can offer certain valuable insights for the machining of this material. 展开更多
关键词 7075 aluminum alloy boring bar vibration reduction particle damping
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