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关于渗流中流线不封闭的特性和条件

力学季刊 2003年第3期24卷 346-350页

作者：陈金娥上海电力学院动力工程系上海200090

本文对于流体在多孔介质中流动的特性进行理论研究和数值计算,提出两个关于渗流中流线不封闭的特性和条件,得到了在一般工程实际情况中的多孔介质区域内部不存在封闭流线的结论。本文以突变截面圆管中不可压缩渗流为算例,利用半人工瞬... 详细信息

本文对于流体在多孔介质中流动的特性进行理论研究和数值计算,提出两个关于渗流中流线不封闭的特性和条件,得到了在一般工程实际情况中的多孔介质区域内部不存在封闭流线的结论。本文以突变截面圆管中不可压缩渗流为算例,利用半人工瞬变方法进行数值计算,得到流体在充满多孔介质的突扩截面圆管和突缩截面圆管中流动时关于速度分布和压力分布的结果。由此表明,在突变截面附近的渗流区域中不存在回流和分离流,也不存在封闭的流线。渗流的这些流动特性不同于在无多孔介质的空间区域中的流动特性。

关键词：渗流流线特性半人工瞬变方法突变截面圆管

Preparation and Characterization of High Conductivity Aluminium Silicon Alloy

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稀有金属材料与工程 2011年第S3期40卷 185-187页

作者： Liao Wenjun1, 2, Wang Yuxin1, Yu Zhang1, Yang Yinhui1, Dong Gang1, Yan Biao1 1Tongji university, shanghai 200092, china 2shanghai electric Group Co., Ltd. Central Academe, shanghai 200070, china Tongji Univ Shanghai Key Lab D&A Met Funct Mat Sch Mat Sci & Engn Shanghai 200092 Peoples R China shanghai Elect Grp Co Ltd Cent Acad Shanghai 200070 Peoples R China

Hypereutectic aluminum-silicon alloy powder of Al-20Si-0.35RE was synthesized by using the inert gas atomization technique. This powder was ball milled for different time and hot extruded subsequently. The microstructure and electrical conductivity of alloy were studied by powder particle size analyzer, scanning electron microscope, X-ray diffraction and bridge resistance instrument respectively. It is indicated that the powder got by spray method have a better homogeneous distribution. The proper RE amount and milling time improved the conductivity due to either microstructural refining or decreasing of Si solid solubility in Al matrix. The conductivity changed with ball milling time, while unique high conductivity (75%IACS) could be achieved after milling for 12 h and hot-extruded 3 times. This kind of high conductivity aluminum-silicon alloy will be a potential conductor material which could be extensively used in the electrical engineering field.

关键词： hypereutectic Al-Si alloy gas atomization hot-extrusion conductivity

Simulation of sludge blanket height in clarifiers

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Journal of shanghai university(English Edition) 2009年第4期13卷 287-291页

作者：周振吴志超王志伟顾国维 School of Energy and Environmental engineering Shanghai University of Electric Power College of Environmental Science and engineering Tongji University

Sludge blanket height （SBH） is an important parameter in the clarifier design, operation and control. Based on an overview and classification of SBH algorithms, a modified SBH algorithm is proposed by incorporating a threshold concentration limit into a relative concentration sharp change algorithm to eliminate the disturbance of compression interfaces on the correct simulation of SBH. Pilot-scale test data are adopted to compare reliability of three SBH algorithms reported in literature and the modified SBH algorithm developed in this paper. Calculated results demonstrate that the three SBH algorithms give results with large deviation （〉 50%） from measured SBH, especially under low solid flux conditions. The modified algorithm is computationally efficient and reliable in matching the measured data. It is incorporated into a one- dimensional clarifier model for stable simulation of pilot-scale experimental clarifier data and into dynamic simulation of a full-scale wastewater treatment plant （WWTP） clarifier data.

关键词： clarifier sludge blanket height (SBH) simulation wastewater treatment

Fault Rules Research on Stator Windings Internal Short-circuit of Doubly-fed Wind Generator

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Fault Rules Research on Stator Windings Internal Short-circu...

计及分布式电源的配电网潮流和断线故障分析算法

2010 The 3rd International Conference on power Electronics and Intelligent Transportation System (PEITS 2010)

作者： WEI Shurong and FU Yang department of electric power and Automation engineering shanghai university of electric power shanghai,china

When occurrence of doubly-fed wind generator stator winding slight internal short circuit,the three-phase stator current changes very little,but the Park 'vector figure of threephase stator current has the obvious changes in *** paper test mode of action on doubly-fed machine,draw the Park‘vector figure between normal and inter-turn short circuit conditions. Through the shape and the width of comparison of the Park' Vector track,we can determine whether internal short circuit and estimate the severity of short-circuit,and further obtain the internal short circuit fault rules of double-fed wind generator stator winding.

关键词： Doubly-fed machine stator-winding internal short circuit the Park' Vector track fault rules

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上海交通大学学报 2008年第12期42卷 2028-2032,2036页

作者：刘波张焰杨娜上海交通大学电气工程系上海200240

介绍了分布式电源(DG)与配电网互联的两种常用接口方式,对异步发电机和太阳能电池两种典型DG的运行方式和控制特性进行了研究.建立了各自在潮流计算中所需的数学模型,提出了计及两种DG的交直流混合迭代潮流计算方法,并在此基础上通过考... 详细信息

介绍了分布式电源(DG)与配电网互联的两种常用接口方式,对异步发电机和太阳能电池两种典型DG的运行方式和控制特性进行了研究.建立了各自在潮流计算中所需的数学模型,提出了计及两种DG的交直流混合迭代潮流计算方法,并在此基础上通过考虑配电网特性对灵敏度分析法进行简化,使得该方法能够快速求解断线故障模式下的系统状态,也适合于计及不同DG形式的多电源配电网系统.通过对Kumamoto 15节点配电网系统进行测试,验证了所提出的潮流计算方法以及故障算法的有效性和合理性,为进一步研究DG对电网的影响奠定了基础.

关键词：分布式电源潮流计算灵敏度配电网故障分析

power Network Parameter Estimation Method Based on Data Mining Technology

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Journal of shanghai Jiaotong university(Science) 2008年第4期13卷 468-472页

作者：张启平王承民侯志俭 department of electrical engineering Shanghai Jiaotong University

The parameter values which actually change with the circumstances, weather and load level etc. produce great effect to the result of state estimation. A new parameter estimation method based on data mining technology was proposed. The clustering method was used to classify the historical data in supervisory control and data acquisition （SCADA） database as several types. The data processing technology was implied to treat the isolated point, missing data and yawp data in samples for classified groups. The measurement data which belong to each classification were introduced to the linear regression equation in order to gain the regression coefficient and actual parameters by the least square method. A practical system demonstrates the high correctness, reliability and strong practicability of the proposed method.

关键词： parameter estimation data processing data mining clustering analysis linear regression

A NEW DEPTH-AVERAGED TWO-EQUATION(?) TURBULENT CLOSURE MODEL

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Journal of Hydrodynamics 1989年第3期1卷 47-54页

作者： Yu Li-ren, Dept. of Thermodynamical engineering, shanghai Institute of electric power, shanghai P.R. chinaZhang Shu-nong, Institute of Environmental Science, Hohai university, Nanjing, P.R. china

Based on the revised turbulent k-w model, a new depth-averaged two-equation closure model is offered in this paper. Through numerical investigation, it is shown that the - model has the same order of accuracy as the - model in predicting the eddy regions produced by side temprature jets with transverse currents, but the newly developed model is better than the - model in predicting the jet width,

关键词： In TURBULENT CLOSURE MODEL A NEW DEPTH-AVERAGED TWO-EQUATION

CFD simulation of pressure fluctuation characteristics in the gas-solid fluidized bed:Comparisons with experiments

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Petroleum Science 2011年第2期8卷 211-218页

作者： Wang Qingcheng Zhang Kai Gu Hongyan Beijing Shenwu Thermal Energy Technology Co. LTD Beijing 102200 China State Key Laboratory of Heavy Oil Processing China University of Petroleum Beijing 102249 China National engineering Lab for Biomass power Generation Equipment North China Electric Power University Beijing 102206 China electrical engineering College Guizhou University Guiyang 550025 China

A simple hydrodynamic model based on two-fluid theory, taking into account the effect of discrete particles on both the gas- and solid-phase momentum equations, was used to numerically investigate the pressure fluctuation characteristics in a gas-solid fluidized bed with the aid of CFX 4.4, a commercial CFD software package, by adding user-defined Fortran subroutines. Numerical simulations together with typical experimental measurements show that pressure fluctuations originate above the distributor when a gas pulse is injected into the fluidized bed. The pressure above the bubble gradually increases due to the presence of a rising bubble. When the bubble passes through the bed surface, the pressure near the bed surface gradually decreases to a lower value. Moreover, the pressure signals in the bubbling fluidized beds show obviously periodic characteristics. The major frequency of pressure fluctuations at the same vertical position is affected slightly by the operating gas velocity, and the amplitude of pressure fluctuations is related to both the operating gas velocity and the vertical height. In this study, the influence of the operating gas velocity on the pressure wave propagation velocity can be ignored, and only two peak frequencies in the power spectrum of the pressure fluctuations are observed which are associated with the bubble formation above the distributor and its eruption at the bed surface.

关键词： Gas-solid fluidized bed CFD simulation experimental measurements propagation ofpressure fluctuations pressure wave velocity pressure fluctuation frequency

Measurement of Swarm Parameters of c-C_4F_8/CO_2 and Its Insulation Characteristics Analysis

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Journal of shanghai Jiaotong university(Science) 2008年第4期13卷 448-452页

作者：张刘春肖登明张栋吴变桃 department of electrical engineering Shanghai Jiaotong University

In c-C4F8 and c-C4F8/CO2 mixtures, the swarm parameters including ionization coefficient, attachment coefficient and effective ionization coefficient were obtained at the ratio of the electric field strength to the gas density between 150-550 Td by the steady-state Townsend （SST） method. Static breakdown voltages at each ratio were also measured at the SST condition. The limiting field strengths were obtained by two methods： computing the density-normalized effective ionization coefficient as a function of the overall density-reduced electric field strength; and measuring static breakdown voltages as a function of the product of gas density and electrode separation. Good agreement was obtained by these two methods, which ensures the correctness of the former method. The limiting field strengths of c-C4F8 and c-C4F8/CO2 mixtures were compared with those of pure SF6, 8F6/602 mixtures and pure c-C4F8. It is found that buffer gas CO2 does not reduce the limiting field strengths of c-C4F8 greatly, the limiting field strengths of c-C4F8/CO2 mixtures are higher than those of SF6/CO2 mixtures or even pure SF6, and so c-C4F8/CO2 mixtures are suggested to be possible substitutes for SF6.

关键词： c-C4F8/CO2 SF6 steady state Townsend (SST) swarm parameters dielectric strength