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Comparative Study on Different Methods for Prediction of Thermal Insulation Performance of Thermal Barrier Coating Used on Turbine Blades

2011年

作者： zeng xiaodong

来源：畅想之星图书光盘版（南... 评论

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Journal of Thermal Science 2024年第1期33卷 172-189页

作者： ZHANG Zhixin zeng Wu ZHANG xiaodong zeng Yuntao Advanced Gas Turbine Laboratory Institute of Engineering ThermophysicsChinese Academy of SciencesBeijing 100190China Key Laboratory of Advanced Energy and Power Institute of Engineering ThermophysicsChinese Academy of SciencesBeijing 100190China Innovation Academy for Light-duty Gas Turbine Chinese Academy of SciencesBeijing 100190China University of Chinese Academy of Sciences Beijing 100049China

As turbine inlet temperature gets higher and higher,thermal barrier coating(TBC) is more and more widely used in turbine blades.For turbine blades with TBC,it is of great significance to evaluate the temperature distribution of its substrate metal quickly and accurately,especially during the design stage.With different degrees of simplification such as whether to consider the change of the geometric size of the fluid domain by TBC and whether to consider the planar heat conduction in TBC,three different methods used in conjugate heat transfer(CHT) simulation to model the TBC of the turbine blades have been developed and widely used by researchers.However,little research has been conducted to investigate the influence of the three methods on the temperature distribution of turbine blade.To fill this gap,three geometric models were designed.They are a solid conduction model with a substrate metal layer and a TBC layer,a transonic turbine vane with internal cooling and TBC,and a plate cylindrical film hole cooling model with TBC.Different methods were used in these geometric models and their differences were carefully analyzed and discussed.The result shows that for the conduction model used in this paper,with the same TBC surface temperature distribution,the difference between the three methods is very small and can be ignored.For a transonic turbine vane with internal cooling,regarding the local maximum temperature of the substrate-TBC interface,the largest difference between the method in which TBC is considered as a thermal resistance or a virtual layer of cells and the method in which three-dimensional heat conduction equation of TBC is solved occurs at the trailing edge.The difference near the leading edge is below 2K.When employed to the film cooling model,the difference of the laterally averaged temperature of the substrate-TBC interface can be 8 K which is mainly due to the change of the length to diameter ratio of the film cooling hole by TBC.If the substrate thickness is reduced by the thickness of TBC wh

关键词： turbine blade thermal barrier coating conjugate heat transfer film cooling hole

Trend in seasonal amplitude of northern net ecosystem production:Simulated results from IAP DGVM in CAS-ESM2

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Atmospheric and Oceanic Science Letters 2024年第2期17卷 45-51页

作者： Jiawen Zhu Xiaodong ZENG International Center for Climate and Environment Sciences Institute of Atmospheric PhysicsChinese Academy of SciencesBeijingChina Collaborative Innovation Center on Forecast and Evaluation of Meteorological Disasters(CIC-FEMD) Nanjing University of Information Science&TechnologyNanjingChina University of Chinese Academy of Sciences BeijingChina

北方陆地净生态系统生产力(NEP)具有明显的季节变化特征,这是大气CO_(2)季节变化的关键驱动.研究这些碳循环过程并理解潜在的驱动因素是气候研究的一个关键问题.本文利用第二代中国科学院地球系统模式(CAS-ESM2)中的全球植被动态模型(IA... 详细信息

北方陆地净生态系统生产力(NEP)具有明显的季节变化特征,这是大气CO_(2)季节变化的关键驱动.研究这些碳循环过程并理解潜在的驱动因素是气候研究的一个关键问题.本文利用第二代中国科学院地球系统模式(CAS-ESM2)中的全球植被动态模型(IAPDGVM),研究了1990-2014年北方NEP(40°-90°N)的季节振幅及其变化趋势.在初始化试验的基础上,本文开展了一个控制试验来评估模拟的北方NEP季节幅度的变化趋势,同时开展了三个敏感性试验来研究气候和大气CO_(2)的贡献.结果表明:1990-2014年,模拟的北方NEP季节振幅显著增加,趋势为9.69万吨碳/月/年,这主要是由于最大NEP增加所致.当分别排除CO_(2)施肥效应和气候效应时,上述增加趋势大大减弱.这些显著的减少表明大气CO_(2)和气候变化对北方NEP的季节性振幅有重要影响.尽管模式存在不确定性,但这些结果有利于进一步提升IAPDGVM对陆地碳循环的精确模拟,也为CAS-ESM研究碳-气候相互作用的应用提供了重要参考.

关键词：净生态系统生产力北方陆地生态系统季节变化幅度 CO_(2)施肥效应气候效应

Assessment of Crop Yield in China Simulated by Thirteen Global Gridded Crop Models

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Advances in Atmospheric Sciences 2024年第3期41卷 420-434页

作者： Dezhen YIN Fang LI Yaqiong LU Xiaodong ZENG Zhongda LIN Yanqing ZHOU International Center for Climate and Environment Sciences Institute of Atmospheric PhysicsChinese Academy of SciencesBeijing 100029China University of Chinese Academy of Sciences Beijing 100049China Institute of Mountain Hazards and Environment Chinese Academy of SciencesChengdu 610041China State Key Laboratory of Numerical Modeling for Atmospheric Sciences and Geophysical Fluid Dynamics Institute of Atmospheric PhysicsChinese Academy of SciencesBeijing 100029China State Key Laboratory of Desert and Oasis Ecology Xinjiang Institute of Ecology and GeographyChinese Academy of SciencesUrumqi 830011China

Global gridded crop models(GGCMs) have been broadly applied to assess the impacts of climate and environmental change and adaptation on agricultural production. China is a major grain producing country, but thus far only a few studies have assessed the performance of GGCMs in China, and these studies mainly focused on the average and interannual variability of national and regional yields. Here, a systematic national-and provincial-scale evaluation of the simulations by13 GGCMs [12 from the GGCM Intercomparison(GGCMI) project, phase 1, and CLM5-crop] of the yields of four crops(wheat, maize, rice, and soybean) in China during 1980–2009 was carried out through comparison with crop yield statistics collected from the National Bureau of Statistics of China. Results showed that GGCMI models generally underestimate the national yield of rice but overestimate it for the other three crops, while CLM5-crop can reproduce the national yields of wheat, maize, and rice well. Most GGCMs struggle to simulate the spatial patterns of crop yields. In terms of temporal variability, GGCMI models generally fail to capture the observed significant increases, but some can skillfully simulate the interannual variability. Conversely, CLM5-crop can represent the increases in wheat, maize, and rice, but works less well in simulating the interannual variability. At least one model can skillfully reproduce the temporal variability of yields in the top-10 producing provinces in China, albeit with a few exceptions. This study, for the first time, provides a complete picture of GGCM performance in China, which is important for GGCM development and understanding the reliability and uncertainty of national-and provincial-scale crop yield prediction in China.

关键词： global gridded crop model historical crop yield China multi-model evaluation

Smartphone-based bridge frequency identification using vehicle contact-point response

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Earthquake Engineering and Engineering Vibration 2023年第4期22卷 1031-1043页

作者： Liu Chengyin Zhu Yipeng zeng Qing Wu xiaodong Shenzhen Key Laboratory of Intelligent Structure System in Civil Engineering Harbin Institute of TechnologyShenzhen 518055China

Bridge frequency(BF)identification using the vehicle scanning method has attracted considerable attention during the last two decades.However,most previous studies have adopted unrealistic vehicle models,thus finding limited practical applications.This study proposes a smartphone-based BF identification method that uses the contact-point acceleration response of a four degree-of-freedom vehicle model.The said response can be inferred from the vehicle body response measured by a smartphone.For realizing practical applications,this method is incorporated into a self-developed smartphone app to obtain data smoothly and identify BFs in a timely manner.Numerical and experimental investigations are performed to verify the effectiveness of the proposed method.In particular,the robustness of this method is investigated numerically against various factors,including the vehicle speed,bridge span,road roughness,and bridge type.Furthermore,laboratory calibration tests are performed to investigate the accuracy of the smartphone gyroscope in measuring the angular velocity,where anomalous data are detected and eliminated.Laboratory experiment results for a simply supported bridge indicate that the proposed method can be used to identify the first two BFs with acceptable accuracy.

关键词： bridge frequency(BF)identification vehicle–bridge interaction four degree-of-freedom(DOF)vehicle model contact-point response smartphone

Solving Time Dependent Fokker-Planck Equations via Temporal Normalizing Flow

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Communications in Computational Physics 2022年第7期32卷 401-423页

作者： xiaodong Feng Li zeng Tao Zhou LSEC Institute of Computational Mathematics and Scientific/Engineering ComputingAMSSChinese Academy of SciencesBeijingChina

In this work,we propose an adaptive learning approach based on temporal normalizing flows for solving time-dependent Fokker-Planck(TFP)equations.It is well known that solutions of such equations are probability density functions,and thus our approach relies on modelling the target solutions with the temporal normalizing flows.The temporal normalizing flow is then trained based on the TFP loss function,without requiring any labeled data.Being a machine learning scheme,the proposed approach is mesh-free and can be easily applied to high dimensional problems.We present a variety of test problems to show the effectiveness of the learning approach.

关键词： Temporal normalizing flow Fokker-Planck equations adaptive density approximation

Changes in Global Vegetation Distribution and Carbon Fluxes in Response to Global Warming:Simulated Results from IAP-DGVM in CAS-ESM2

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Advances in Atmospheric Sciences 2022年第8期39卷 1285-1298,I0002-I0010页

作者： Xiaofei GAO Jiawen ZHU Xiaodong ZENG Minghua ZHANG Yongjiu DAI Duoying JI He ZHANG International Center for Climate and Environment Sciences Institute of Atmospheric PhysicsChinese Academy of SciencesBeijing 100029China University of Chinese Academy of Sciences Beijing 100049China Collaborative Innovation Center on Forecast and Evaluation of Meteorological Disasters Nanjing University of Information Science and TechnologyNanjing 210044China School of Marine and Atmospheric Sciences Stony Brook UniversityNY 11790USA School of Atmospheric Sciences Sun Yat-Sen UniversityGuangzhou 510275China College of Global Change and Earth System Science Beijing Normal UniversityBeijing 100875China

Terrestrial ecosystems are an important part of Earth systems,and they are undergoing remarkable changes in response to global warming.This study investigates the response of the terrestrial vegetation distribution and carbon fluxes to global warming by using the new dynamic global vegetation model in the second version of the Chinese Academy of Sciences(CAS)Earth System Model(CAS-ESM2).We conducted two sets of simulations,a present-day simulation and a future simulation,which were forced by the present-day climate during 1981-2000 and the future climate during 2081-2100,respectively,as derived from RCP8.5 outputs in CMIP5.CO_(2)concentration is kept constant in all simulations to isolate CO_(2)-fertilization effects.The results show an overall increase in vegetation coverage in response to global warming,which is the net result of the greening in the mid-high latitudes and the browning in the tropics.The results also show an enhancement in carbon fluxes in response to global warming,including gross primary productivity,net primary productivity,and autotrophic respiration.We found that the changes in vegetation coverage were significantly correlated with changes in surface air temperature,reflecting the dominant role of temperature,while the changes in carbon fluxes were caused by the combined effects of leaf area index,temperature,and precipitation.This study applies the CAS-ESM2 to investigate the response of terrestrial ecosystems to climate warming.Even though the interpretation of the results is limited by isolating CO_(2)-fertilization effects,this application is still beneficial for adding to our understanding of vegetation processes and to further improve upon model parameterizations.

关键词： global warming vegetation distribution carbon flux leaf area index surface air temperature

Changes in the seasonal amplitude of northern ecosystem productivity under future global warming

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Atmospheric and Oceanic Science Letters 2023年第3期16卷 1-6页

作者： Jiawen Zhu Xiaofei Gao Xiaodong ZENG International Center for Climate and Environment Sciences Institute of Atmospheric PhysicsChinese Academy of SciencesBeijingChina Collaborative Innovation Center on Forecast and Evaluation of Meteorological Disasters(CIC-FEMD) Nanjing University of Information Science&TechnologyNanjingChina University of Chinese Academy of Sciences BeijingChina

观测显示过去几十年北半球大气二氧化碳季节幅度大幅增加,这主要是由北半球陆地净生态系统生产力季节幅度的增加所致。但是,因为气候变化和植被动态的不确定性,未来陆地净生态系统生产力季节幅度的变化还很不清楚.本工作利用全球植被动... 详细信息

观测显示过去几十年北半球大气二氧化碳季节幅度大幅增加,这主要是由北半球陆地净生态系统生产力季节幅度的增加所致。但是,因为气候变化和植被动态的不确定性,未来陆地净生态系统生产力季节幅度的变化还很不清楚.本工作利用全球植被动力学模式研究了全球变暖背景下北纬45°以北陆地净生态系统生产力季节幅度的变化.作者做了两大类试验:当代试验(1981-2000)和CMIP5RCP8.5变暖情景驱动的未来试验(2081-2100).结果显示,在RCP8.5变暖情景下北半球中高纬陆地净生态系统生产力季节幅度整体增加,这是因为陆地净生态系统生产力的月最大值增加且月最小值减小.最大(最小)陆地净生态系统生产力的增加(减小)是由于总初级生产力的增加强(弱)于生态系统总呼吸,总初级生产力和生态系统总呼吸的变化都主要受地表气温和植被动态的驱动.本工作强调了植被动态对北半球中高纬陆地生态系统碳循环的关键调制作用,也强调了在地球系统模式中包含全球植被动力学模式的重要性。

关键词：陆地生态系统碳循环全球变暖植被动态碳循环的季节变化

Soil microbial attributes along a chronosequence of Scots pine(Pinus sylvestris var. mongolica) plantations in northern China

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Pedosphere 2020年第4期30卷 433-442页

作者： xiaodong YAO Wenjing zeng Hui zeng Wei WANG Department of Ecology College of Urban and Environment Sciences and Key Laboratory for Earth Surface Processes of the Ministry of EducationPeking UniversityBeijing 100871(China) School of Urban Planning and Design Peking University Shenzhen University TownShenzhen 518055(China)

Soil microorganisms play a key role in soil organic matter dynamics, nutrient cycling, and soil fertility maintenance in forest ecosystems, and they are influenced by stand age and soil depth. However, few studies have simultaneously considered these two factors. In this study, we measured soil microbial biomass carbon (SMBC), soil microbial biomass nitrogen (SMBN), soil basal respiration (SBR) rate, and potential extracellular enzyme activity (EEA) in soil to a depth of 60 cm under 10-, 30-, and 40-year-old Scots pine (Pinus sylvestris var. mongolica) stands (Y10, Y30, and Y40, respectively) in plantations in northern China in 2011. Soil water content (SWC), soil pH, soil organic carbon (SOC), and soil total nitrogen (STN) were also measured to explore their effects on soil microbial indices across different stand ages and soil depths. Our results showed that SMBC, SMBN, and the SBR rate were generally higher for the Y30 stand than for the Y10 and Y40 stands. Potential EEA, except forα-glucosidase, decreased significantly with increasing stand age. Soil organic carbon,STN, SWC, and soil pH explained 67%of the variation in soil microbial attributes among the three stand ages. For the same stand age, soil microbial biomass and the SBR rate decreased with soil depth. Lower microbial biomass, lower SBR rate, and lower EEA for the mature Y40 stand indicate lower substrate availability for soil microorganisms, lower soil quality, and lower microbial adaptability to the environment. Our results suggest that changes in soil quality with stand age should be considered when determining the optimum rotation length of plantations and the best management practices for afforestation programs.

关键词： soil microbial metabolism quotient(gCO2) soil basal respiration soil depth soil microbial biomass soil organic matter dynamics soil potential extracellular enzyme activity stand age

Development of an Establishment Scheme for a DGVM

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Advances in Atmospheric Sciences 2016年第7期33卷 829-840页

作者： Xiang SONG Xiaodong ZENG Jiawen ZHU Pu SHAO International Center for Climate and Environment Sciences Institute of Atmospheric PhysicsChinese Academy of SciencesBeijing 100029 Collaborative Innovation Center on Forecast and Evaluation of Meteorological Disasters Nanjing University of lnformation Science&TechnologyNanjing 210044 University of Chinese Academy of Sciences Beijing 100049

Environmental changes are expected to shift the distribution and abundance of vegetation by determining seedling estab- lishment and success. However, most current ecosystem models only focus on the impacts of abiotic factors on biogeophysics （e.g., global distribution, etc.）, ignoring their roles in the population dynamics （e.g., seedling establishment rate, mortality rate, etc.） of ecological communities. Such neglect may lead to biases in ecosystem population dynamics （such as changes in population density for woody species in forest ecosystems） and characteristics. In the present study, a new establishment scheme for introducing soil water as a function rather than a threshold was developed and validated, using version 1.0 of the IAP-DGVM as a test bed. The results showed that soil water in the establishment scheme had a remarkable influence on forest transition zones. Compared with the original scheme, the new scheme significantly improved simulations of tree population density, especially in the peripheral areas of forests and transition zones. Consequently, biases in forest fractional coverage were reduced in approximately 78.8% of the global grid cells. The global simulated areas of tree, shrub, grass and bare soil performed better, where the relative biases were reduced from 34.3% to 4.8%, from 27.6% to 13.1%, from 55.2% to 9.2%, and from 37.6% to 3.6%, respectively. Furthermore, the new scheme had more reasonable dependencies of plant functional types （PFTs） on mean annual precipitation, and described the correct dominant PFTs in the tropical rainforest peripheral areas of the Amazon and central Africa.

关键词： establishment scheme soil water IAP-DGVM1.0 forest population density fractional coverage