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Mechanism of internal thermal runaway propagation in blade batteries 被引量:3
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作者 Xuning Feng Fangshu Zhang +3 位作者 Wensheng Huang Yong Peng Chengshan Xu Minggao Ouyang 《Journal of Energy Chemistry》 SCIE EI CAS CSCD 2024年第2期184-194,I0005,共12页
Blade batteries are extensively used in electric vehicles,but unavoidable thermal runaway is an inherent threat to their safe use.This study experimentally investigated the mechanism underlying thermal runaway propaga... Blade batteries are extensively used in electric vehicles,but unavoidable thermal runaway is an inherent threat to their safe use.This study experimentally investigated the mechanism underlying thermal runaway propagation within a blade battery by using a nail to trigger thermal runaway and thermocouples to track its propagation inside a cell.The results showed that the internal thermal runaway could propagate for up to 272 s,which is comparable to that of a traditional battery module.The velocity of the thermal runaway propagation fluctuated between 1 and 8 mm s^(-1),depending on both the electrolyte content and high-temperature gas diffusion.In the early stages of thermal runaway,the electrolyte participated in the reaction,which intensified the thermal runaway and accelerated its propagation.As the battery temperature increased,the electrolyte evaporated,which attenuated the acceleration effect.Gas diffusion affected thermal runaway propagation through both heat transfer and mass transfer.The experimental results indicated that gas diffusion accelerated the velocity of thermal runaway propagation by 36.84%.We used a 1D mathematical model and confirmed that convective heat transfer induced by gas diffusion increased the velocity of thermal runaway propagation by 5.46%-17.06%.Finally,the temperature rate curve was analyzed,and a three-stage mechanism for internal thermal runaway propagation was proposed.In Stage I,convective heat transfer from electrolyte evaporation locally increased the temperature to 100℃.In Stage II,solid heat transfer locally increases the temperature to trigger thermal runaway.In StageⅢ,thermal runaway sharply increases the local temperature.The proposed mechanism sheds light on the internal thermal runaway propagation of blade batteries and offers valuable insights into safety considerations for future design. 展开更多
关键词 Lithium-ion battery Blade battery Thermal runaway Internal thermal runaway propagation
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Surfactant-assisted doctor-blading-printed FAPbBr3 films for efficient semitransparent perovskite solar cells 被引量:1
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作者 Hangkai YING Yifan LIU +5 位作者 Yuxi DOU Jibo ZHANG Zhenli WU Qi ZHANG Yi-Bing CHENG Jie ZHONG 《Frontiers of Optoelectronics》 EI CSCD 2020年第3期272-281,共10页
Organic-inorganic hybrid perovskite solar cells have generated wide interest due to the rapid development of their photovoltaic conversion effciencies.However,the majority of the reported devices have been fabricated ... Organic-inorganic hybrid perovskite solar cells have generated wide interest due to the rapid development of their photovoltaic conversion effciencies.However,the majority of the reported devices have been fabricated via spin coating with a device areaof<1 cm2.In this study,we fabricated a wide-bandgap formamidi-nium lead bromide(FAPbBr3)film using a cost-effective,high-yielding doctor-blade-coating process.The effects of different surfactants,such as I-α-phosphatidylcholine,polyoxyethylene sorbitan monooleate,sodium lauryl sulfonate,and hexadecyl trimethyl ammonium bromide,were studied during the printing process.Accompanying the optimization of the blading temperature,crystal sizes of over 10μm and large-area perovskite films of5cm×5 cm were obtained using this method.The printed FAPbBr3 solar cells exhibited a short-circuit current density of 8.22 mA/cm2,an open-circuit voltage of 1.175 V,and an efficiency of 7.29%.Subsequently,we replaced the gold with silver nanowires as the top electrode to prepare a semitransparent perovskite solar cell with an average transmittance(400-800 nm)of 25.42%,achieving a high-power efficiency of 5.11%.This study demonstrates efficient doctor-blading printing for preparing large-area FAPbBr3 films that possess high potential for applications in building integrated photovoltaics. 展开更多
关键词 SEMITRANSPARENT printing perovskite solar cell(PSC) doctor blading wide bandgap
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风电机组电气与机械联合仿真研究 被引量:1
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作者 赵伟 曾庆忠 +1 位作者 刘佳佳 曾东 《东方电气评论》 2024年第1期39-42,共4页
本文基于GH Bladed软件建立风电机组电气与机械联合仿真平台,通过主控及发电系统自定义模型,与Bladed内置模型进行正确交互,针对电网电压故障的故障程度、故障类型、穿越策略等因素,分析风电机组电气与机械相互作用机理与特性。以上因... 本文基于GH Bladed软件建立风电机组电气与机械联合仿真平台,通过主控及发电系统自定义模型,与Bladed内置模型进行正确交互,针对电网电压故障的故障程度、故障类型、穿越策略等因素,分析风电机组电气与机械相互作用机理与特性。以上因素均能通过直接影响发电机电磁暂态过渡过程对结构载荷产生影响,并且不同故障因素对机组部件载荷的影响具有其规律性。 展开更多
关键词 风电机组 Bladed软件 电气机械联合仿真
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On the beginning of the Japanese Upper Paleolithic:A review of recent archaeological and anthropological evidence
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作者 Hiroyuki SATO Kazuki MORISAKI 《人类学学报》 CSSCI CSCD 北大核心 2024年第3期470-487,共18页
The beginning of the Japanese Upper Paleolithic has mainly been examined using two major models:the Middle Paleolithic evolutionary model within the archipelago and the continental Upper Paleolithic diffusion/migratio... The beginning of the Japanese Upper Paleolithic has mainly been examined using two major models:the Middle Paleolithic evolutionary model within the archipelago and the continental Upper Paleolithic diffusion/migration model.However,recent archeological data from Japan and nearby countries are challenging such simple models.This paper critically reviews previous chronology of the Japanese Paleolithic,including possible Lower and Middle Paleolithic(LP/MP),and attempts to show an alternative model of the beginning of the Japanese Upper Paleolithic.This paper suggests several possible specimens of LP/MP and recommends further geoarchaeological investigation to understand the reliability and cultural relationship between possible LP/MP specimens and the Early Upper Paleolithic(EUP).The start of the Japanese EUP is presently characterized by a flake industry with trapezoids and denticulates around 39-37 kaBP cal on Paleo-Honshu Island,which has partial resemblance with contemporary assemblages in China and the Korean Peninsula,although trapezoids are endemic only to the Japanese EUP and may have derived from the ancestral lithic tradition.Blade technology appeared earliest on Central Paleo-Honshu Island,about 1000 years later than the earliest flake technology.Although blade technology may have originated from the elongated flake technology of the previous period,the sudden simultaneous emergence implies that it diffused from the Korean Peninsula.This paper proposes that blade technology from the Korean Peninsula arrived on the northeastern Paleo-Honshu Island,including the Japan Sea coastal region of western Honshu,rather than the southwest,where flake technology long prospered,due to differences in ecological settings and adaptation strategies between the two regions. 展开更多
关键词 Japanese Archipelago Early Upper Paleolithic migration route TRAPEZOID denticulate blade technology
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Chemical vapor deposition for perovskite solar cells and modules
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作者 Zhihao Tao Yuxuan Song +2 位作者 Baochang Wang Guoqing Tong Liming Ding 《Journal of Semiconductors》 EI CAS CSCD 2024年第4期1-4,共4页
Metal halide perovskites are promising materials for solar cells because of high power conversion efficiency(PCE),tun-able bandgap,high defect tolerance,long carrier diffusion length,and low-cost fabrication[1-7].The ... Metal halide perovskites are promising materials for solar cells because of high power conversion efficiency(PCE),tun-able bandgap,high defect tolerance,long carrier diffusion length,and low-cost fabrication[1-7].The PCE for perovskite solar cells(PSCs)reaches 26.14%for single-junction cells,29.1%for perovskite/perovskite tandem cells and 33.9%for perovskite/silicon tandem cells,being comparable to that for silicon and other thin-film solar cells[8-10].Perovskite solar cells have been made by solution methods including spin-coat-ing,blade coating and printing[11,12]. 展开更多
关键词 PEROVSKITE BLADE FILM
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Numerical simulation on directional solidification and heat treatment processes of turbine blades
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作者 Ye-yuan Hu Ju-huai Ma Qing-yan Xu 《China Foundry》 SCIE EI CAS CSCD 2024年第5期476-490,共15页
Study on turbine blades is crucial due to their critical role in ensuring the efficient and reliable operation of aircraft engines.Nickel-based single crystal superalloys are extensively used in the hot manufacturing ... Study on turbine blades is crucial due to their critical role in ensuring the efficient and reliable operation of aircraft engines.Nickel-based single crystal superalloys are extensively used in the hot manufacturing of turbine blades due to their exceptional high-temperature mechanical properties.The hot manufacturing of single crystal blades involves directional solidification and heat treatment.Experimental manufacturing of these blades is time-consuming,capital-intensive,and often insufficient to meet industrial demands.Numerical simulation techniques have gained widespread acceptance in blade manufacturing research due to their low energy consumption,high efficiency,and rapid turnaround time.This article introduces the modeling and simulation of hot manufacturing in single crystal blades.The discussion outlines the prevalent mathematical models employed in numerical simulations related to blade hot manufacturing.It encapsulates the advancements in research concerning macro to micro-level numerical simulation techniques for directional solidification and heat treatment processes.Furthermore,potential future trajectories for the numerical simulation of single crystal blade hot manufacturing are also discussed. 展开更多
关键词 single crystal blades Ni-based superalloy directional solidification heat treatment numerical simulation
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Optimized Design of Bio-Inspired Wind Turbine Blades
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作者 Yuanjun Dai Dong Wang +1 位作者 Xiongfei Liu Weimin Wu 《Fluid Dynamics & Materials Processing》 EI 2024年第7期1647-1664,共18页
To enhance the aerodynamic performance of wind turbine blades,this study proposes the adoption of a bionic airfoil inspired by the aerodynamic shape of an eagle.Based on the blade element theory,a non-uniform extracti... To enhance the aerodynamic performance of wind turbine blades,this study proposes the adoption of a bionic airfoil inspired by the aerodynamic shape of an eagle.Based on the blade element theory,a non-uniform extraction method of blade elements is employed for the optimization design of the considered wind turbine blades.Moreover,Computational Fluid Dynamics(CFD)is used to determine the aerodynamic performances of the eagle airfoil and a NACA2412 airfoil,thereby demonstrating the superior aerodynamic performance of the former.Finally,a mathematical model for optimizing the design of wind turbine blades is introduced and a comparative analysis is conducted with respect to the aerodynamic performances of blades designed using a uniform extraction approach.It is found that the blades designed using non-uniform extraction exhibit better aerodynamic performance. 展开更多
关键词 AIRFOIL wind turbines blade design CFD
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Blade Wrap Angle Impact on Centrifugal Pump Performance:Entropy Generation and Fluid-Structure Interaction Analysis
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作者 Hayder Kareem Sakran Mohd Sharizal Abdul Aziz Chu Yee Khor 《Computer Modeling in Engineering & Sciences》 SCIE EI 2024年第7期109-137,共29页
The centrifugal pump is a prevalent power equipment widely used in different engineering patterns,and the impeller blade wrap angle significantly impacts its performance.A numerical investigation was conducted to anal... The centrifugal pump is a prevalent power equipment widely used in different engineering patterns,and the impeller blade wrap angle significantly impacts its performance.A numerical investigation was conducted to analyze the influence of the blade wrap angle on flow characteristics and energy distribution of a centrifugal pump evaluated as a low specific speed with a value of 69.This study investigates six impellermodels that possess varying blade wrap angles(95°,105°,115°,125°,135°,and 145°)that were created while maintaining the same volute and other geometrical characteristics.The investigation of energy loss was conducted to evaluate the values of total and entropy generation rates(TEG,EGR).The fluid-structure interaction was considered numerically using the software tools ANSYS Fluent and ANSYSWorkbench.The elastic structural dynamic equation was used to estimate the structural response,while the shear stress transport k–ωturbulence model was utilized for the fluid domain modeling.The findings suggest that the blade wrap angle has a significant influence on the efficiency of the pump.The impeller featuring a blade wrap angle of 145°exhibits higher efficiency,with a notable increase of 3.76%relative to the original model.Variations in the blade wrap angle impact the energy loss,shaft power,and pump head.The model with a 145°angle exhibited a maximum equivalent stress of 14.8MPa and a total deformation of 0.084 mm.The results provide valuable insights into the intricate flow mechanism of the centrifugal pump,particularly when considering various blade wrap angles. 展开更多
关键词 Centrifugal pump blade wrap angle entropy generation theory fluid-structure interaction hydraulic performance
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Influence of Surface Ice Roughness on the Aerodynamic Performance of Wind Turbines
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作者 Xin Guan Mingyang Li +2 位作者 Shiwei Wu Yuqi Xie Yongpeng Sun 《Fluid Dynamics & Materials Processing》 EI 2024年第9期2029-2043,共15页
The focus of this research was on the equivalent particle roughness height correction required to account for the presence of ice when determining the performances of wind turbines.In particular,two icing processes(fr... The focus of this research was on the equivalent particle roughness height correction required to account for the presence of ice when determining the performances of wind turbines.In particular,two icing processes(frost ice and clear ice)were examined by combining the FENSAP-ICE and FLUENT analysis tools.The ice type on the blade surfaces was predicted by using a multi-time step method.Accordingly,the influence of variations in icing shape and ice surface roughness on the aerodynamic performance of blades during frost ice formation or clear ice formation was investigated.The results indicate that differences in blade surface roughness and heat flux lead to disparities in both ice formation rate and shape between frost ice and clear ice.Clear ice has a greater impact on aerodynamics compared to frost ice,while frost ice is significantly influenced by the roughness of its icy surface. 展开更多
关键词 Wind turbine icing blade surface roughness aerodynamic characteristics AIRFOIL
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Research on Automatic Test System of Engine Blade Natural Frequency
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作者 LU Yonghua LIU Jingjing +2 位作者 YANG Haibo HUANG Chuan MA Zhicheng 《Transactions of Nanjing University of Aeronautics and Astronautics》 EI CSCD 2024年第4期476-487,共12页
Blades are one of the important components on aircraft engines.If they break due to vibration failure,the normal operation of the entire engine will be offected.Therefore,it is necessary to measure their natural frequ... Blades are one of the important components on aircraft engines.If they break due to vibration failure,the normal operation of the entire engine will be offected.Therefore,it is necessary to measure their natural frequency before installing them on the engine to avoid resonance.At present,most blade vibration testing systems require manual operation by operators,which has high requirements for operators and the testing process is also very cumbersome.Therefore,the testing efficiency is low and cannot meet the needs of efficient testing.To solve the current problems of low testing efficiency and high operational requirements,a high-precision and high-efficiency automatic test system is designed.The testing accuracy of this system can reach ±1%,and the testing efficiency is improved by 37% compared to manual testing.Firstly,the influence of compression force and vibration exciter position on natural frequency test is analyzed by amplitude-frequency curve,so as to calibrate servo cylinder and fourdimensional motion platform.Secondly,the sine wave signal is used as the excitation to sweep the blade linearly,and the natural frequency is determined by the amplitude peak in the frequency domain.Finally,the accuracy experiment and efficiency experiment are carried out on the developed test system,whose results verify its high efficiency and high precision. 展开更多
关键词 BLADE vibration failure natural frequency automatic test system
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Optimization of a Pipeline-Type Savonius Hydraulic Turbine
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作者 Xiaohui Wang Kai Zhang +3 位作者 Xiaobang Bai Senchun Miao Zanxiu Wu Jicheng Li 《Fluid Dynamics & Materials Processing》 EI 2024年第5期1123-1146,共24页
This study focuses on a DN50 pipeline-type Savonius hydraulic turbine.The torque variation of the turbine in a rotation cycle is analyzed theoretically in the framework of the plane potential flow theory.Related numer... This study focuses on a DN50 pipeline-type Savonius hydraulic turbine.The torque variation of the turbine in a rotation cycle is analyzed theoretically in the framework of the plane potential flow theory.Related numerical simulations show that the change in turbine torque is consistent with the theoretical analysis,with the main power zone and the secondary power zone exhibiting a positive torque.In contrast,the primary resistance zone and the secondary resistance zone are characterized by a negative torque.Analytical relationships between the turbine’s internal flow angleθ,the deflector’s inclination angleα0,and the coverage angleαof the power zone are introduced,and a method for calculating the optimal number of blades is proposed to maximize the power zone.Results are presented about performance tests conducted on five groups of hydraulic turbines with the blade number ranging from 3 to 7.Such results indicate that both the turbine’s recovery power and efficiency attain the highest values when the blade number is 4,which is in agreement with the number of blades calculated by the proposed method.Additionally,the study examines the effects of the flow rate on turbine parameters and the projected energy generation and cost savings for a specific pipeline configuration. 展开更多
关键词 Savonius turbine blade number numerical simulation experimental study benefit prediction
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Influence of Blade Number on the Performance of Hydraulic Turbines in the Transition Stage
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作者 Fengxia Shi Guangbiao Zhao +1 位作者 Yucai Tang Dedong Maand Xiangyun Shi 《Fluid Dynamics & Materials Processing》 EI 2024年第11期2617-2636,共20页
To analyze the effect of blade number on the performance of hydraulic turbines during the transient stage in which theflow rate is not constant,six hydraulic turbines with different blade numbers are considered.The ins... To analyze the effect of blade number on the performance of hydraulic turbines during the transient stage in which theflow rate is not constant,six hydraulic turbines with different blade numbers are considered.The instantaneous hydraulic performance of the turbine and the pressure pulsation acting on the impeller are investigated numerically by using the ANSYS CFX software.The ensuing results are compared with the outcomes of experimental tests.It is shown that thefluctuation range of the pressure coefficient increases with time,but the corresponding range for the transient hydraulic efficiency decreases gradually when theflow velocity transits to larger values.During the transition to smallflow velocity,thefluctuation range of the pressure coefficient gradually decreases as time passes,but the correspondingfluctuation range of its transient hydraulic efficiency gradually becomes larger.Thefluctuation range in the Z9 case is small during the transition.The main frequency of transient hydraulic efficiency pulsation is equal to the blade frequency.At the main frequency,Z7 has the largest amplitude of the hydraulic efficiency pulsation,Z10 has the smallest amplitude,and the difference between Z7 and Z9 is limited.As the number of blades grows,the pressure pulsation during the transition process gradually decreases,but the pressure pulsation of Z10 at the volute tongue is larger.In the steady state,Z9 has the highest efficiency and in the transient stage,the pressure coefficientfluctuation range is small.Accordingly,for the hydraulic turbine Z9,the performance is optimal. 展开更多
关键词 Hydraulic turbine blade number transient process pressurefluctuation transient hydraulic performance
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Research on the Icing Diagnosis ofWind Turbine Blades Based on FS–XGBoost–EWMA
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作者 Jicai Guo Xiaowen Song +5 位作者 Chang Liu Yanfeng Zhang Shijie Guo JianxinWu Chang Cai Qing’an Li 《Energy Engineering》 EI 2024年第7期1739-1758,共20页
In winter,wind turbines are susceptible to blade icing,which results in a series of energy losses and safe operation problems.Therefore,blade icing detection has become a top priority.Conventional methods primarily re... In winter,wind turbines are susceptible to blade icing,which results in a series of energy losses and safe operation problems.Therefore,blade icing detection has become a top priority.Conventional methods primarily rely on sensor monitoring,which is expensive and has limited applications.Data-driven blade icing detection methods have become feasible with the development of artificial intelligence.However,the data-driven method is plagued by limited training samples and icing samples;therefore,this paper proposes an icing warning strategy based on the combination of feature selection(FS),eXtreme Gradient Boosting(XGBoost)algorithm,and exponentially weighted moving average(EWMA)analysis.In the training phase,FS is performed using correlation analysis to eliminate redundant features,and the XGBoost algorithm is applied to learn the hidden effective information in supervisory control and data acquisition analysis(SCADA)data to build a normal behavior model.In the online monitoring phase,an EWMA analysis is introduced to monitor the abnormal changes in features.A blade icing warning is issued when themonitored features continuously exceed the control limit,and the ambient temperature is below 0℃.This study uses data fromthree icing-affected wind turbines and one normally operating wind turbine for validation.The experimental results reveal that the strategy can promptly predict the icing trend among wind turbines and stably monitor the normally operating wind turbines. 展开更多
关键词 Wind turbine blade icing feature selection XGBoost EWMA
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Assessment of Similitude Behavior in Natural Frequencies of Printed Turbine Blade
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作者 MUHAMMAD Usman Safdar SHEN Xing EIMAN B.Saheby 《Transactions of Nanjing University of Aeronautics and Astronautics》 EI CSCD 2024年第4期488-501,共14页
Improving structures involves comparing old and new designs on a key parameter.Calculating the percent change in performance is a method to assess.This paper proposes a cost-effective analogy by generating replicas of... Improving structures involves comparing old and new designs on a key parameter.Calculating the percent change in performance is a method to assess.This paper proposes a cost-effective analogy by generating replicas of additive manufactured aluminum alloy(Al Si10Mg)body-centered cubic lattice(BCC)based turbine blade(T106C)with the same in poly-lactic acid(PLA)material and their comparison in the context of percent change for natural frequencies.Initially,a cavity is created inside the turbine blade(hollow blade).Natural frequencies are obtained experimentally and numerically by incorporating BCC at 50%and 80%of the cavity length into the hollow blade for both materials.The cost of manufacturing the metal blades is 90%more than that of the PLA blades.The two material blade designs show a similar percentage variation,as the first-order mode enhancs more than 5%and the second-order mode more than 4%.To observe the behavior in another material,both blades are analyzed numerically with a nickel-based U-500 material,and the same result is achieved,describing that percent change between designs can be verified using the PLA material. 展开更多
关键词 AlSi10Mg poly-lactic acid(PLA) U-500 T106C blade BCC lattice structure
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Climate change and human health: Last call to arms for us
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作者 Antonio Corrente Maria Caterina Pace Marco Fiore 《World Journal of Clinical Cases》 SCIE 2024年第11期1870-1874,共5页
Climate change,now the foremost global health hazard,poses multifaceted challenges to human health.This editorial elucidates the extensive impact of climate change on health,emphasising the increasing burden of diseas... Climate change,now the foremost global health hazard,poses multifaceted challenges to human health.This editorial elucidates the extensive impact of climate change on health,emphasising the increasing burden of diseases and the exacerbation of health disparities.It highlights the critical role of the healthcare sector,particularly anaesthesia,in both contributing to and mitigating climate change.It is a call to action for the medical community to recognise and respond to the health challenges posed by climate change. 展开更多
关键词 Climate change Carbon footprint Sustainability Greenhouse gases Anaesthetic gases Environmental impact Disposable laryngoscope blades
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Effect of Rigid Pitch Motion on Flexible Vibration Characteristics of a Wind Turbine Blade
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作者 Zhan Wang Liang Li +3 位作者 Long Wang Weidong Zhu Yinghui Li Echuan Yang 《Energy Engineering》 EI 2024年第10期2981-3000,共20页
Adynamic pitch strategy is usually adopted to improve the aerodynamic performance of the blade of awind turbine.The dynamic pitch motion will affect the linear vibration characteristics of the blade.However,these infl... Adynamic pitch strategy is usually adopted to improve the aerodynamic performance of the blade of awind turbine.The dynamic pitch motion will affect the linear vibration characteristics of the blade.However,these influences have not been studied in previous research.In this paper,the influences of the rigid pitch motion on the linear vibration characteristics of a wind turbine blade are studied.The blade is described as a rotating cantilever beam with an inherent coupled rigid-flexible vibration,where the rigid pitch motion introduces a parametrically excited vibration to the beam.Partial differential equations governing the nonlinear coupled pitch-bend vibration are proposed using the generalized Hamiltonian principle.Natural vibration characteristics of the inherent coupled rigid-flexible system are analyzed based on the combination of the assumed modes method and the multi-scales method.Effects of static pitch angle,rotating speed,and characteristics of harmonic pitch motion on flexible natural frequencies andmode shapes are discussed.It shows that the pitch amplitude has a dramatic influence on the natural frequencies of the blade,while the effects of pitch frequency and pith phase on natural frequencies are little. 展开更多
关键词 Pitch motion wind turbine blade inherent rigid-flexible coupling vibration characteristics
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Nonlinear Flap-Wise Vibration Characteristics ofWind Turbine Blades Based onMulti-Scale AnalysisMethod
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作者 Qifa Lang Yuqiao Zheng +2 位作者 Tiancai Cui Chenglong Shi Heyu Zhang 《Energy Engineering》 EI 2024年第2期483-498,共16页
This work presents a novel approach to achieve nonlinear vibration response based on the Hamilton principle.We chose the 5-MW reference wind turbine which was established by the National Renewable Energy Laboratory(NR... This work presents a novel approach to achieve nonlinear vibration response based on the Hamilton principle.We chose the 5-MW reference wind turbine which was established by the National Renewable Energy Laboratory(NREL),to research the effects of the nonlinear flap-wise vibration characteristics.The turbine wheel is simplified by treating the blade of a wind turbine as an Euler-Bernoulli beam,and the nonlinear flap-wise vibration characteristics of the wind turbine blades are discussed based on the simplification first.Then,the blade’s large-deflection flap-wise vibration governing equation is established by considering the nonlinear term involving the centrifugal force.Lastly,it is truncated by the Galerkin method and analyzed semi-analytically using the multi-scale analysis method,and numerical simulations are carried out to compare the simulation results of finite elements with the numerical simulation results using Campbell diagram analysis of blade vibration.The results indicated that the rotational speed of the impeller has a significant impact on blade vibration.When the wheel speed of 12.1 rpm and excitation amplitude of 1.23 the maximum displacement amplitude of the blade has increased from 0.72 to 3.16.From the amplitude-frequency curve,it can be seen that the multi-peak characteristic of blade amplitude frequency is under centrifugal nonlinearity.Closed phase trajectories in blade nonlinear vibration,exhibiting periodic motion characteristics,are found through phase diagrams and Poincare section diagrams. 展开更多
关键词 Wind turbine blades nonlinear vibration Galerkin method multi-scales method
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Surface Defect Detection and Evaluation Method of Large Wind Turbine Blades Based on an Improved Deeplabv3+Deep Learning Model
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作者 Wanrun Li Wenhai Zhao +1 位作者 Tongtong Wang Yongfeng Du 《Structural Durability & Health Monitoring》 EI 2024年第5期553-575,共23页
The accumulation of defects on wind turbine blade surfaces can lead to irreversible damage,impacting the aero-dynamic performance of the blades.To address the challenge of detecting and quantifying surface defects on ... The accumulation of defects on wind turbine blade surfaces can lead to irreversible damage,impacting the aero-dynamic performance of the blades.To address the challenge of detecting and quantifying surface defects on wind turbine blades,a blade surface defect detection and quantification method based on an improved Deeplabv3+deep learning model is proposed.Firstly,an improved method for wind turbine blade surface defect detection,utilizing Mobilenetv2 as the backbone feature extraction network,is proposed based on an original Deeplabv3+deep learning model to address the issue of limited robustness.Secondly,through integrating the concept of pre-trained weights from transfer learning and implementing a freeze training strategy,significant improvements have been made to enhance both the training speed and model training accuracy of this deep learning model.Finally,based on segmented blade surface defect images,a method for quantifying blade defects is proposed.This method combines image stitching algorithms to achieve overall quantification and risk assessment of the entire blade.Test results show that the improved Deeplabv3+deep learning model reduces training time by approximately 43.03%compared to the original model,while achieving mAP and MIoU values of 96.87%and 96.93%,respectively.Moreover,it demonstrates robustness in detecting different surface defects on blades across different back-grounds.The application of a blade surface defect quantification method enables the precise quantification of dif-ferent defects and facilitates the assessment of risk levels associated with defect measurements across the entire blade.This method enables non-contact,long-distance,high-precision detection and quantification of surface defects on the blades,providing a reference for assessing surface defects on wind turbine blades. 展开更多
关键词 Structural health monitoring computer vision blade surface defects detection Deeplabv3+ deep learning model
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Research on Fatigue Damage Behavior of Main Beam Sub-Structure of Composite Wind Turbine Blade
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作者 Haixia Kou Bowen Yang +2 位作者 Xuyao Zhang Xiaobo Yang Haibo Zhao 《Structural Durability & Health Monitoring》 EI 2024年第3期277-297,共21页
Given the difficulty in accurately evaluating the fatigue performance of large composite wind turbine blades(referred to as blades),this paper takes the main beam structure of the blade with a rectangular cross-sectio... Given the difficulty in accurately evaluating the fatigue performance of large composite wind turbine blades(referred to as blades),this paper takes the main beam structure of the blade with a rectangular cross-sectionas the simulation object and establishes a composite laminate rectangular beam structure that simultaneouslyincludes the flange,web,and adhesive layer,referred to as the blade main beam sub-structure specimen,throughthe definition of blade sub-structures.This paper examines the progressive damage evolution law of the compositelaminate rectangular beam utilizing an improved 3D Hashin failure criterion,cohesive zone model,B-K failurecriterion,and computer simulation technology.Under static loading,the layup angle of the anti-shear web hasa close relationship with the static load-carrying capacity of the composite laminate rectangular beam;under fatigueloading,the fatigue damage will first occur in the lower flange adhesive area of the whole composite laminaterectangular beam and ultimately result in the fracture failure of the entire structure.These results provide a theoreticalreference and foundation for evaluating and predicting the fatigue performance of the blade main beamstructure and even the full-size blade. 展开更多
关键词 Composite laminate wind turbine blade sub-structure progressive damage analysis user material subroutine cohesive zone model
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旋转带肋通道流阻特性研究
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作者 由儒全 许云腾 李海旺 《风机技术》 2024年第2期51-61,共11页
With the development of aero-engines, the turbine inlet temperature continues to rise. In order to ensure the safety and reliability of the turbine blades, cooling structures must be set inside turbine blades to cool ... With the development of aero-engines, the turbine inlet temperature continues to rise. In order to ensure the safety and reliability of the turbine blades, cooling structures must be set inside turbine blades to cool them. Heat transfer coefficient and flow resistance are the key parameters to measure the cooling characteristics of internal cooling structures. In this paper, the characteristics of flow resistance in a rotating ribbed channel is presented numerical simulation under different rib spacings, rib angles, and thermal boundary conditions. The results show that, separation and reattachment of fluid between ribs is the key effect of rib spacing on flow resistance. The flow resistance is small when the rib spacing is small, because it's difficult for the fluid to form reattachment between the ribs. With the increase of rib spacing, the reattachment phenomenon is more obvious and the flow resistance increases accordingly. In general,p: e=10 channel has the maximum flow resistance. Secondary flow caused by the ribs is the key factor affecting the flow resistance characteristics with different rib angles. The secondary flow interacts with the main flow and causes flow loss through mixing, thus affecting the flow resistance of the channel. Under static condition, the flow resistance of 60°ribbed channel is the largest. The flow resistance of channel was affected by the temperature rise ratio also. And with the increase of the Ro, the temperature rise ratio has a more obvious effect on the flow resistance of the ribbed channel.When Ro=0.45, the flow resistance of the channel with a temperature rise ratio of 0.4 is 2.4 times that of the channel without temperature rise, while when Ro=0.3, it is 1.6 times, and when Ro=0.15, it is 1.2 times. 展开更多
关键词 Blade Cooling Ribbed Passage ROTATION Flow Resistance Characteristics
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