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A thermal flux-diffusing model for complex networks and its applications in community structure detection
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作者 沈毅 《Chinese Physics B》 SCIE EI CAS CSCD 2013年第5期637-643,共7页
We introduce a thermal flux-diffusing model for complex networks. Based on this model, we propose a physical method to detect the communities in the complex networks. The method allows us to obtain the temperature dis... We introduce a thermal flux-diffusing model for complex networks. Based on this model, we propose a physical method to detect the communities in the complex networks. The method allows us to obtain the temperature distribution of nodes in time that scales linearly with the network size. Then, the local community enclosing a given node can be easily detected for the reason that the dense connections in the local communities lead to the temperatures of nodes in the same community being close to each other. The community structure of a network can be recursively detected by randomly choosing the nodes outside the detected local communities. In the experiments, we apply our method to a set of benchmarking networks with known pre-determined community structures. The experiment results show that our method has higher accuracy and precision than most existing globe methods and is better than the other existing local methods in the selection of the initial node. Finally. several real-world networks are investigated. 展开更多
关键词 complex networks community structure thermal flux-diffusing model
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Impact of Cattaneo-Christov Heat Flux in the Nanofluid Flow over an Inclined Permeable Surface with Irreversibility Analysis
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作者 Muhammad Ramzan Hina Gul 《Journal of Applied Mathematics and Physics》 2024年第4期1582-1595,共14页
This study discusses the magnetohydrodynamic nanofluid flow over an inclined permeable surface influenced by mixed convection, and Cattaeo-Christov heat flux. The heat transfer analysis is performed in the presence of... This study discusses the magnetohydrodynamic nanofluid flow over an inclined permeable surface influenced by mixed convection, and Cattaeo-Christov heat flux. The heat transfer analysis is performed in the presence of a heat source/sink and thermal stratification. To gauge the energy loss during the process, an irreversibility analysis is also performed. A numerical solution to the envisaged problem is obtained using the bvp4c package of MATLAB. Graphs are drawn to assess the consequences of the arising parameters against the associated profiles. The results show that an augmentation in the magnetic field and nanomaterial volume fraction results in an enhancement in the temperature profile. A strong magnetic field can significantly reduce the fluid velocity. The behavior of the Skin friction coefficient against the different estimates of emerging parameters is discussed. . 展开更多
关键词 Nanofluid Flow Cattaneo-Christov Heat flux Permeable Surface Mixed Convection Heat Source/Sink thermal Stratification
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Thermal fronts and cross-frontal heat flux in the southern Huanghai Sea and the East China Sea 被引量:2
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作者 PARK Sunghyea CHU Peter C 《Acta Oceanologica Sinica》 SCIE CAS CSCD 2008年第5期1-20,共20页
Synoptic features in/around thermal fronts and cross-frontal heat fluxes in the southern Huanghai./Yellow Sea and East China Sea (HES) were examined using the data collected from four airborne expendable bathythermo... Synoptic features in/around thermal fronts and cross-frontal heat fluxes in the southern Huanghai./Yellow Sea and East China Sea (HES) were examined using the data collected from four airborne expendable bathythermograph surveys with horizontal approxmately 35 km and vertical 1 m(from the surface to 400 m deep) spacings. Since the fronts are strongly affected by HES current system, the synoptic thermal features in/around them represent the interaction of currents with surrounding water masses. These features can not be obtained from climatological data. The identified thermal features are listed as follows : ( 1 ) multiple boundaries of cold water, asymmetric thermocline intrusion, locally-split front by homogeneous water of approxmately 18 ℃, and mergence of the front by the Taiwan Warm Current in/around summertime southern Cheju - Changjiang/Yangtze front and Tsushima front; (2) springtime frontal eddy-like feature around Tsushima front; (3) year-round cyclonic meandering and summertime temperature-inversion at the bottom of the surface mixed layer in Cheju - Tsushima front; and (4) multistructure of Kuroshio front. In the Kuroshio front the mean variance of vertical temperature gradient is an order of degree smaller than that in other HES fronts. The southern Cheju- Changjiang front and Cheju -Tsushima front are connected with each other in the summer with comparable cross-frontal temperature gradient. However, cross-frontal heat flux and lateral eddy diffusivity are stronger in the southern Cheju - Changjiang front. The cross-frontal heat exchange is the largest in the mixing zone between the modified Huanghai Sea bottom cold water and the Tsushima Warm Current, which is attributable to enhanced thermocline intrusions. 展开更多
关键词 southern Huanghai Sea and East China Sea AXBT synoptic thermal front cross-frontal heat flux lateral eddy diffusivity
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Modal and Thermal Analysis of a Modified Connecting Rod of an Internal Combustion Engine Using Finite Element Method
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作者 Nkrumah Jacob Kwaku Baba Ziblim +1 位作者 Sulemana Yahaya Sherry Kwabla Amedorme 《Modeling and Numerical Simulation of Material Science》 2023年第3期29-49,共21页
The connecting rod is one of the most important moving components in an internal combustion engine. The present work determined the possibility of using aluminium alloy 7075 material to design and manufacture a connec... The connecting rod is one of the most important moving components in an internal combustion engine. The present work determined the possibility of using aluminium alloy 7075 material to design and manufacture a connecting rod for weight optimisation without losing the strength of the connecting rod. It considered modal and thermal analyses to investigate the suitability of the material for connecting rod design. The parameters that were considered under the modal analysis were: total deformation, and natural frequency, while the thermal analysis looked at the temperature distribution, total heat flux and directional heat flux of the four connecting rods made with titanium alloy, grey cast iron, structural steel and aluminium 7075 alloy respectively. The connecting rod was modelled using Autodesk inventor2017 software using the calculated parameters. The steady-state thermal analysis was used to determine the induced heat flux and directional heat flux. The study found that Aluminium 7075 alloy deformed more than the remaining three other materials but has superior qualities in terms of vibrational natural frequency, total heat flux and lightweight compared to structural steel, grey cast iron and titanium alloy. 展开更多
关键词 Connecting Rod Steady-State thermal Analysis DEFORMATION Heat flux thermal and Modal Finite Element Method
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Investigation the Correlation between Thermal Bridging and Geometries in Concrete Buildings
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作者 Ali Vaseghi Craig Capano 《Journal of Building Construction and Planning Research》 2023年第4期87-100,共14页
This article focuses on the investigation of the correlation between thermal bridging and various geometric configurations. The article employs QuickField software for conducting three-dimensional steady-state heat tr... This article focuses on the investigation of the correlation between thermal bridging and various geometric configurations. The article employs QuickField software for conducting three-dimensional steady-state heat transfer simulations to investigate the thermal behaviors of diverse geometric shapes. Significantly, this study involves the simulation of four distinct geometries including concrete circular, square, rectangular, and triangular column through an insulated concrete layer while all geometries maintain the consistent surface areas. The simulations yield findings indicating that circular thermal bridging has the best thermal performance, while rectangular thermal bridging displays comparatively the lowest thermal efficiency. Furthermore, the results indicate that alterations in the perimeter of thermal bridge interfaces, while maintaining a constant area, exert a more pronounced influence on the thermal performance of the geometries compared to proportional changes in area while preserving the perimeter. The study’s findings aid building designers and architects in creating more energy-efficient structural and architectural elements by incorporating thermally efficient geometries and forms. . 展开更多
关键词 thermal Bridging Heat flux Building Energy Building Envelope Concrete Building
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Adaptive nodeless variable finite elements with flux-based formulation for thermal-structural analysis
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作者 Sutthisak Phongthanapanich Pramote Dechaumphai 《Acta Mechanica Sinica》 SCIE EI CAS CSCD 2008年第2期181-188,共8页
A nodeless variable element method with the fluxbased formulation is developed to analyze two-dimensional thermal-structural problems. The nodeless variable formula- tion provides accurate temperature distributions to... A nodeless variable element method with the fluxbased formulation is developed to analyze two-dimensional thermal-structural problems. The nodeless variable formula- tion provides accurate temperature distributions to yield more accurate thermal stress solutions. The flux-based formulation is used to reduce the complexity in deriving the finite element equations as compared to the conventional finite element method. The solution accuracy is further improved by implementing an adaptive meshing technique to generate finite element meshes that can adapt and move along with the transient solution behavior. A version of a nearly optimal element size determination is proposed to provide high convergence rate of the predicted solutions. The combined procedure is evaluated by solving several thermal, structural, and thermal stress problems. 展开更多
关键词 Keywords flux-based formulation Nodeless variablefinite element method thermal stress
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Steady thermal hydraulic characteristics of nuclear steam generators based on the drift flux code model
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作者 张小英 陈焕栋 +3 位作者 白宁 朱元兵 任志豪 黄凯 《Nuclear Science and Techniques》 SCIE CAS CSCD 2014年第5期78-85,共8页
To investigate the steady thermal hydraulic characteristics of U-tube steam generator(SG), a 1D simulation code based on the four-equation drift flux model is developed. The U-tube channels presumably consist mainly o... To investigate the steady thermal hydraulic characteristics of U-tube steam generator(SG), a 1D simulation code based on the four-equation drift flux model is developed. The U-tube channels presumably consist mainly of the primary channel, secondary channel, and tube wall. In the sub-cooling regions of the primary and secondary channels, flow is simulated using the single-phase flow model, whereas that in the boiling regions of the secondary channels is simulated using the four-equation drift flux model. The first-order equations of upwind difference are derived based on the staggered grid. Steady-state thermal hydraulic parameters are obtained with a cross-iteration scheme of heat balance and natural circulation requirement. The developed code is applied to analyze the SG behavior of the Qinshan I Nuclear Power Plant under 100%, 75%, 50%, 30%, and 15% power conditions. Analysis results are then compared with the simulation results obtained using RELAP5. 展开更多
关键词 热工水力特性 漂移流模型 蒸汽发生器 秦山核电站 代码 基础 通量 一维模拟
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Numerical Study by Imposing the Finite Difference Method for Unsteady Casson Fluid Flow with Heat Flux
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作者 Ali H. Tedjani 《Journal of Applied Mathematics and Physics》 2023年第12期3826-3839,共14页
This article presents an investigation into the flow and heat transfer characteristics of an impermeable stretching sheet subjected to Magnetohydrodynamic Casson fluid. The study considers the influence of slip veloci... This article presents an investigation into the flow and heat transfer characteristics of an impermeable stretching sheet subjected to Magnetohydrodynamic Casson fluid. The study considers the influence of slip velocity, thermal radiation conditions, and heat flux. The investigation is conducted employing a robust numerical method that accounts for the impact of thermal radiation. This category of fluid is apt for characterizing the movement of blood within an industrial artery, where the flow can be regulated by a material designed to manage it. The resolution of the ensuing system of ordinary differential equations (ODEs), representing the described problem, is accomplished through the application of the finite difference method. The examination of flow and heat transfer characteristics, including aspects such as unsteadiness, radiation parameter, slip velocity, Casson parameter, and Prandtl number, is explored and visually presented through tables and graphs to illustrate their impact. On the stretching sheet, calculations, and descriptions of the local skin-friction coefficient and the local Nusselt number are conducted. In conclusion, the findings indicate that the proposed method serves as a straightforward and efficient tool for exploring the solutions of fluid models of this kind. 展开更多
关键词 Casson Model Unsteady Stretching Sheet Variable Heat flux MHD Slip Impacts thermal Radiation Finite Difference Method
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高温环境下烧蚀热防护结构隔热性能测试方法
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作者 张婕 吴敬涛 +3 位作者 刘宁夫 陈宏 李昕昕 高哲 《装备环境工程》 CAS 2024年第10期62-69,共8页
目的建立高精度的烧蚀热防护结构隔热性能测试方法。方法分析烧蚀热防护结构地面热试验特点,设计烧蚀热防护结构隔热性能试验方案,提出考虑地面热损失的高精度热载荷模拟方法。采用自研模块化石英灯加热器作为加热装置,设计可重复使用... 目的建立高精度的烧蚀热防护结构隔热性能测试方法。方法分析烧蚀热防护结构地面热试验特点,设计烧蚀热防护结构隔热性能试验方案,提出考虑地面热损失的高精度热载荷模拟方法。采用自研模块化石英灯加热器作为加热装置,设计可重复使用夹具封装试验件和热流计,建立烧蚀热防护结构隔热性能测试装置。结果成功完成了典型烧蚀热防护结构隔热性能考核试验,获得了结构在瞬态和稳态热流条件下的背温数据,试验装置运行稳定可靠,可有效消除热边界效应,保证热流长时测控。试验结果验证了试验边界条件模拟的可重复性、热场均匀性以及良好的控制精度。结论有效解决了烧蚀热防护结构受热后产生明火、浓烟而导致的高温环境模拟难题,为烧蚀热防护结构材料筛选及结构定尺寸设计提供了高精度测试方法。 展开更多
关键词 高超声速飞行器 烧蚀热防护 隔热性能 辐射加热 温度 热流
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卫星有源相控阵高热流微尺度器件热设计与验证
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作者 卢威 李进 +3 位作者 周傲松 陈腾博 智国平 邹雷 《航天器环境工程》 CSCD 2024年第5期574-580,共7页
为解决卫星有源相控阵高热流微尺度器件散热和热试验验证难题,首先,提出T/R模块低温共烧陶瓷热设计优化方案,选择热通孔面积比为11.4%,并建立尺度比为800∶1的跨尺度热模型;其次,进行地面常压热平衡试验,利用红外热像仪测量器件温度;再... 为解决卫星有源相控阵高热流微尺度器件散热和热试验验证难题,首先,提出T/R模块低温共烧陶瓷热设计优化方案,选择热通孔面积比为11.4%,并建立尺度比为800∶1的跨尺度热模型;其次,进行地面常压热平衡试验,利用红外热像仪测量器件温度;再基于热参数敏感性分析方法评估自然对流、热辐射和热传导有关参数对器件温度的影响,结果表明:对于特征长度为600μm的典型器件,接触热导对散热影响最大,而自然对流和热辐射影响均低于2%;基于常压热平衡试验数据修正热模型后的仿真与试验数据吻合良好,最大温度偏差1.7℃;高热流微尺度器件接触热导为16200 W/(m^(2)·K),预示真空下器件的最高温度为73.2℃,满足工程要求。研究结果可为卫星高热流微尺度器件热设计和验证提供参考。 展开更多
关键词 高热流微尺度器件 T/R模块 热设计 自然对流
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基于热电堆的微型热流传感器制备及性能研究 被引量:1
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作者 李晓芬 张香香 谭秋林 《传感器与微系统》 CSCD 北大核心 2024年第5期31-34,共4页
航空发动机内部温度和热辐射的不均匀分布可能导致叶片表面出现热点,引起叶尖等区域的材料损坏。因此,监测单位时间内通过叶片表面的热量十分重要。热电堆型热流传感器以其测量范围广、稳定性好、精度高等优点,成为监测高温环境热流参... 航空发动机内部温度和热辐射的不均匀分布可能导致叶片表面出现热点,引起叶尖等区域的材料损坏。因此,监测单位时间内通过叶片表面的热量十分重要。热电堆型热流传感器以其测量范围广、稳定性好、精度高等优点,成为监测高温环境热流参数的常用方法。本文采用丝网印刷和高温烧结工艺,在10 mm×10 mm×1 mm的99%Al_(2)O_(3)陶瓷基片上制备了Pt-Rh10/Pt热电堆型热流传感器,并搭建了热流实验平台对传感器进行测试。结果表明,该热流传感器在1 019.4℃的高温环境下,所测热流密度为179.67 kW/m^(2),输出电压为0.462 3 mV。经过3次热循环测试可知,该热流传感器的重复性偏差小于5%,具有较好的重复性。 展开更多
关键词 高温环境 热流监测 热阻层 热电效应 热流传感器
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某高热密度风冷机箱热设计与仿真
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作者 王帅 余涛 韩钟剑 《舰船电子工程》 2024年第5期214-217,共4页
论文设计了一种高热流密度强迫风冷机箱,为满足机箱总热耗800W的散热需求,通过风道设计、风阻计算、风机选型对机箱进行散热设计。同时,利用Ansys Icepak分析软件对机箱进行热仿真分析。结果显示,环境温度50℃下,机箱内部安装16个热耗5... 论文设计了一种高热流密度强迫风冷机箱,为满足机箱总热耗800W的散热需求,通过风道设计、风阻计算、风机选型对机箱进行散热设计。同时,利用Ansys Icepak分析软件对机箱进行热仿真分析。结果显示,环境温度50℃下,机箱内部安装16个热耗50 W模块时,发热芯片壳体温度最高为71.4℃;机箱内部安装10个热耗80W模块时,发热芯片壳体温度最高为85.6℃,满足散热设计需求。机箱进出口温差约9.6℃,风机工作点合理,理论计算与仿真结果接近。 展开更多
关键词 高热流密度 强迫风冷机箱 热设计 Ansys Icepak
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中子多芯硼管探测器热中子灵敏度检测研究
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作者 赵国海 张荣华 +5 位作者 李多宏 徐争争 陈金铸 赵冬 贾文宝 韩叶良 《世界核地质科学》 CAS 2024年第4期841-847,共7页
中子探测器用于测量未知中子辐射场的中子信息时,热中子灵敏度是中子探测器的一项重要参数,需提前对其进行热中子灵敏度的检测,以保证数据的可靠性。此外热中子灵敏度也是中子探测器性能优劣的一个重要指标,指导着探测器的改进和应用。... 中子探测器用于测量未知中子辐射场的中子信息时,热中子灵敏度是中子探测器的一项重要参数,需提前对其进行热中子灵敏度的检测,以保证数据的可靠性。此外热中子灵敏度也是中子探测器性能优劣的一个重要指标,指导着探测器的改进和应用。为检测某中子多芯硼管探测器样件的热中子灵敏度,提出一种在非标准中子场下测量热中子灵敏度的实验方法。该方法通过慢化同位素中子源建立含有热中子的中子场,利用活化箔法对探测器所在空间处的热中子注量率进行绝对测量,进而求得该中子探测器的热中子灵敏度。此外,对于不同几何布置下该中子多芯硼管探测器的热中子灵敏度检测结果进行实验分析,确定优选的几何布置。结果表明:该中子多芯硼管具有良好的热中子灵敏度,且测量结果与厂家在标定的结果吻合良好,验证该热中子灵敏度检测方法的可行性与准确性。此实验方法为后续开展探测器的结构设计、优化等提供便利。 展开更多
关键词 中子探测器 热中子灵敏度 热中子注量率
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磷矿热还原制取黄磷技术现状及研究进展
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作者 李明霞 夜晨 +2 位作者 李姗 梅毅 聂云祥 《化工进展》 EI CAS CSCD 北大核心 2024年第7期3578-3592,共15页
黄磷生产属于“高能耗”和“高污染”行业,电炉法是目前唯一的工业化生产黄磷的方法,但存在电耗高、黄磷尾气难以资源化利用等问题。在“碳达峰、碳中和”背景下,深入打好污染防治攻坚战,实现减污降碳协同增效是必然选择,因此,黄磷生产... 黄磷生产属于“高能耗”和“高污染”行业,电炉法是目前唯一的工业化生产黄磷的方法,但存在电耗高、黄磷尾气难以资源化利用等问题。在“碳达峰、碳中和”背景下,深入打好污染防治攻坚战,实现减污降碳协同增效是必然选择,因此,黄磷生产技术亟待创新。本文总结了磷矿热还原制取黄磷的机制,归纳了SiO_(2)、Al_(2)O_(3)和MgO助熔剂以及炭质还原剂活性对磷矿还原的影响,阐述了高炉法、电炉法、流态化法、熔融电解法、低温碳热还原磷酸法、硅热法和磷煤耦合联产黄磷和一氧化碳法制取黄磷的技术原理、特点以及存在的问题。指出未来黄磷生产技术的总体要求是节能降耗和碳资源高效利用,低品位磷矿利用技术和低磷废弃物中回收磷技术的开发对实现磷资源的可持续开发利用具有重要意义。 展开更多
关键词 黄磷 磷矿 助熔剂 热还原 节能降耗
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乌江流域梯级水库群混合期N_(2)O的释放机理及其影响因素
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作者 陈赛男 岳甫均 +2 位作者 侯永梅 刘小龙 李思亮 《地球与环境》 CAS CSCD 北大核心 2024年第5期535-544,共10页
筑坝显著改变了河流生源要素的生物地球化学循环过程,尤其是对氮循环和温室气体N_(2)O产生和释放的影响,已逐渐受到广泛的关注。本文以乌江中上游4个梯级水库为研究对象,通过分析其冬季混合期的溶存N_(2)O和氮形态含量,探讨混合期亚热... 筑坝显著改变了河流生源要素的生物地球化学循环过程,尤其是对氮循环和温室气体N_(2)O产生和释放的影响,已逐渐受到广泛的关注。本文以乌江中上游4个梯级水库为研究对象,通过分析其冬季混合期的溶存N_(2)O和氮形态含量,探讨混合期亚热带深水型水库N_(2)O的产生机理和影响机制,并对水库N_(2)O释放通量进行估算。结果表明,洪家渡、东风、索风营和乌江渡水库水体溶存N_(2)O浓度均处于过饱和状态,表现为N_(2)0的释放源;其释放通量均值分别为:(0.48±0.07)、(0.34±0.04)0.35和(0.91±0.76)μmol/(m^(2)·h),与全球其它湖泊/河流系统相比处于中等水平。本研究发现水库混合期水体N_(2)O主要来自于硝化作用,其中处于富营养状态的乌江渡水库的深层水体可能受到硝化-反硝化耦合作用及反硝化作用的影响,由此产生的高含量N_(2)O通过底层泄水途径成为重要的释放源。综合考虑各水库特征,水库N_(2)O的产生还受到水库调节类型和库龄的间接影响。对比发现使用IPCC对河流-水库系统N_(2)O间接释放系数的估算可能会显著高估鸟江中上游梯级水库群释放潜力。研究结果为未来评估梯级水库群N_(2)O排放水平和梯级开发背景下流域氮的时空格局变化提供了重要的研究参考。 展开更多
关键词 氧化亚氮 排放通量 混合期 梯级水库 乌江
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基于光强方法的双层温敏漆点阵的热流密度测量
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作者 余港龙 朱一丁 《空气动力学学报》 CSCD 北大核心 2024年第6期35-43,I0001,共10页
为提高长时间热流密度测量的精度,提出了一种基于双层温敏漆点阵涂层的热流密度直测技术。该技术运用精细喷涂技术在厚度均匀的透明膜L2的上下表面分别喷涂错位分布的温敏漆点阵L3和L1。结合图像边缘检测和粒子图像测速的询问算法确定... 为提高长时间热流密度测量的精度,提出了一种基于双层温敏漆点阵涂层的热流密度直测技术。该技术运用精细喷涂技术在厚度均匀的透明膜L2的上下表面分别喷涂错位分布的温敏漆点阵L3和L1。结合图像边缘检测和粒子图像测速的询问算法确定温敏漆点阵位置,提取温敏漆喷涂点的光强,由光强-温度标定关系可以测得L1和L3上的温度分布;分别采用Cook-Felderman方法和Fourier导热定律计算热流密度,并与热流密度传感器测量结果进行比较,结合热渗透时间分析不同方法的适用性。结果表明:双层温敏漆点阵方法既能用Cook-Felderman方法捕捉短时间热冲击下的瞬态热流密度,又能用Fourier导热定律测量长时间稳态的热流密度,在高速热流密度测量中有一定的应用前景。 展开更多
关键词 温敏漆 热流密度测量 点阵方法 热渗透时间
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FDM连续挤压成型过程中温度场的有限元分析
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作者 卫朝霞 徐艳 《计算机应用与软件》 北大核心 2024年第7期61-66,共6页
在熔融沉积成型中,针对动态重新划分网格法描述金属流动变形存在计算复杂且工作量大的问题,提出一种连续挤压成型过程中温度场的有限元分析法。通过采用逐次单元法对熔丝在挤压槽内的应力进行分析,得出铝丝与轮槽各接触面上的热流密度,... 在熔融沉积成型中,针对动态重新划分网格法描述金属流动变形存在计算复杂且工作量大的问题,提出一种连续挤压成型过程中温度场的有限元分析法。通过采用逐次单元法对熔丝在挤压槽内的应力进行分析,得出铝丝与轮槽各接触面上的热流密度,建立温度场有限元分析的数学模型。采用热流密度等效法对金属流动变形进行数值分析,减少计算时间,提高CPU效率。利用有限元分析软件对挤出喷头中的温度场进行热力耦合模拟仿真,获得在不同转速下挤压槽内温度场分布等值线图。仿真结果表明,熔丝在挤压成型过程中,温度场分布均匀,总体状态稳定,保证了成型质量,改进后程序运算时间减少30.9%,CPU运行效率优化17.3%。 展开更多
关键词 温度场计算机仿真 回转式FDM挤出喷头 热流密度 热力耦合分析
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Surface latent heat flux anomalies preceding inland earthquakes in China 被引量:4
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作者 Kai Qin Guangmeng Guo Lixin Wu 《Earthquake Science》 CSCD 2009年第5期555-562,共8页
Using data from the National Center for Environmental Prediction (NCEP), the paper analyzed the surface latent heat flux (SLHF) variations for five inland earthquakes occurred in some lake area, moist area and ari... Using data from the National Center for Environmental Prediction (NCEP), the paper analyzed the surface latent heat flux (SLHF) variations for five inland earthquakes occurred in some lake area, moist area and arid area of China during recent years. We used the SLHF daily and monthly data to differentiate the global and seasonal variability from the transient local anomalies. The temporal scale of the observed variations is 1-2 months before and after the earthquakes, and spatial scale is about 10°×10°. The result suggests that the SLHFs adjacent the epicenters all are anomalous high value (〉μ+2σ) 8-30 days before the shocks as compared with past several years of data. Different from the abnormal meteorological phenomenon, the distribution of the anomalies was isolated and local, which usually occurred in the epicenter and its adjacent area, or along the fault lines. The increase of SLHF was tightly related with the season which the earthquake occurs in; the maximal (125 W/m^2, Pu'er earthquake) and minimal (25 W/m^2, Gaize earthquake) anomalies were in summer and winter, respectively. The abundant surface water and groundwater in the epicenter and its adjacent region can provide necessary condition for the change of SLHF. To further confirm the reliability of SLHF anomaly, it is necessary to explore its physical mechanism in depth by more earthquake cases. 展开更多
关键词 inland earthquake surface latent heat flux thermal anomaly satellite data
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MHD boundary layer flow of Casson fluid passing through an exponentially stretching permeable surface with thermal radiation 被引量:2
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作者 Swati Mukhopadhyay Iswar Chandra Moindal Tasawar Hayat 《Chinese Physics B》 SCIE EI CAS CSCD 2014年第10期306-314,共9页
This article numerically examines the boundary layer flow due to an exponentially stretching surface in the presence of an applied magnetic field. Casson fluid model is used to characterize the non-Newtonian fluid beh... This article numerically examines the boundary layer flow due to an exponentially stretching surface in the presence of an applied magnetic field. Casson fluid model is used to characterize the non-Newtonian fluid behavior. The flow is subjected to suction/blowing at the surface. Analysis is carded out in presence of thermal radiation and prescribed surface heat flux. In this study, an exponential order stretching velocity and prescribed exponential order surface heat flux are accorded with each other. The governing partial differential equations are first converted into nonlinear ordinary differential equations by using appropriate transformations and then solved numerically. The effect of increasing values of the Casson parameter is to suppress the velocity field. However the temperature is enhanced when Casson parameter increases. It is found that the skin-friction coefficient increases with increasing values of suction parameter. Temperature also increases for large values of power index n in both suction and blowing cases at the boundary. It is observed that the thermal radiation enhances the effective thermal diffusivity and hence the temperature rises. 展开更多
关键词 exponential stretching suction/blowing prescribed heat flux thermal radiation
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Evaluation of Haney-Type Surface ThermalBoundary Conditions Using a CoupledAtmosphere and Ocean Model 被引量:1
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作者 Peter C. Chu 陈玉春 吕世华 《Advances in Atmospheric Sciences》 SCIE CAS CSCD 2001年第3期355-375,共21页
A coupled atmosphere-ocean model developed at the Institute for Space Studies at NASA Goddard Space Flight Center (Russell et al., 1995) was used to verify the validity of Haney-type surface thermal boundary condition... A coupled atmosphere-ocean model developed at the Institute for Space Studies at NASA Goddard Space Flight Center (Russell et al., 1995) was used to verify the validity of Haney-type surface thermal boundary condition, which linearly connects net downward surface heat fluxQ to air/sea temperature difference ΔT by a relaxation coefficientk. The model was initiated from the National Centers for Environmental Prediction (NCEP) atmospheric observations for 1 December 1977, and from the National Ocean Data Center (NODC) global climatological mean December temperature and salinity fields at 1°x 1° resolution. The time step is 7.5 minutes. We integrated the model for 450 days and obtained a complete model-generated global data set of daily mean downward net surface fluxQ, surface air temperatureT A, and sea surface temperatureT O. Then, we calculated the cross-correlation coefficients (CCC) betweenQ and ΔT. The ensemble mean CCC fields show (a) no correlation betweenQ and ΔT in the equatiorial regions, and (b) evident correlation (CCC≥0.7) betweenQ and ΔT in the middle and high latitudes. Additionally, we did the variance analysis and found that whenk=120 W m?2K?1, the two standard deviations, σQ and σκδT , are quite close in the middle and high latitudes. These results agree quite well with a previous research (Chu et al., 1998) on analyzing the NCEP re-analyzed surface data, except that a smaller value ofk (80 W m?2K?1) was found in the previous study. Key words Air-sea coupled system - Ocean surface fluxes - Surface thermal boundary condition 展开更多
关键词 Air-sea coupled system Ocean surface fluxes Surface thermal boundary condition
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