检索结果-南通市图书馆

Torque model of hydro turbine with inner energy loss characteristics

Science china(Technological Sciences) 2010年第10期53卷 2826-2832页

作者： ZENG Yun1,2, GUO YaKun2, ZHANG LiXiang1, XU TianMao3.& DONG HongKui4 1 Construction Engineering College, kunming University of Science and Technology, kunming 650051, china 2 School of Engineering, University of Aberdeen, Aberdeen AB24 3.E, UK 3.Computing Center, kunming University of Science and Technology, kunming 650051, china 4 hydraulic energy department, yunnan electric power test and Research institute, kunming 650217, china Construction Engineering College Kunming University of Science and Technology Kunming China School of Engineering University of Aberdeen Aberdeen UK Computing Center Kunming University of Science and Technology Kunming China hydraulic energy department Yunnan Electric Power Test and Research Institute Kunming China

This paper presents the result and analysis of the composition of energy loss occurring in the hydro turbine. Two new types of energy losses,namely the hydraulic loss in the flow channel and the impact loss,are defined. All losses within the hydro turbine are divided into four types and the loss coefficients are defined accordingly. Expressions or characteristic descriptions of these losses as well as the calibration method of the loss coefficients are presented. Furthermore,the torque model of the hydro turbine where the inner energy loss takes place is established. The developed model has been used to calculate the power loss due to the mechanical friction generated by the units’ rotation to solve the difficulty of measurements of the mechanical friction loss in the hydro turbine. The definition of the impact loss explains the phenomenon that the loss of no-load is greater than that of the rated operation. A set of conversion coefficients are defined using the characteristic parameters at the rated operation,which are used to transform the parameters in the torque model into those that are easily measured. Therefore,the expression of the hydro turbine power is converted into a function that has the main servomotor displacement as its single variable. This makes the proposed model be convenient to use. Finally,the proposed model and methods are calibrated and verified using the measured data of a hydropower plant. Good agreement between the modeled results and the measurements indicates that the proposed model can represent the inner energy loss characteristics of the hydro turbine.

关键词： hydraulic loss in flow channel impact loss loss coefficients conversion coefficients

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Numerical simulation of ski-jump jet motion using lattice Boltzmann method

引用

Science china(Technological Sciences) 2011年第S1期54卷 72-75页

作者： ZHANG Hua 1 &ZHANG XiaoDong 2 1 School of Renewable energy,North china electric {3. University,Beijing 102206,china 2 School of energy {3. and Mechanical Engineering,North china electric {3. University,Beijing 102206,china School of Renewable energy North China Electric Power University Beijing China School of energy power and Mechanical Engineering North China Electric Power University Beijing China

Based on the lattice Boltzmann method,a lattice Boltzmann(LB) model of the ski-jump jet two-phase flow is developed first and the corresponding boundary conditions are studied.A simple case study of a droplet horizontal movement calculation is carried out to test and verify the model,where level set method is used to track and reconstruct the moving droplet free surface. Then,we numerically simulate a two dimensional flow field of the ski-jump jet with the LB model,derive the moving surface and velocity vector field of the jet *** simulation results are very consistent with the physical *** effectiveness and reliability of the model are demonstrated by the numerical examples.

关键词： ski-jump jet droplet lattice Boltzmann method interface numerical simulation

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Ecological hydraulic radius model to calculate instream flow requirements for transporting sediment in the western water transfer region

引用

Science china(Technological Sciences) 2009年第11期52卷 3401-3405页

作者： MEN BaoHui1 & LIU ChangMing2 1 Renewable energy institute, North china {3. power University, Beijing 102206, china 2 Key Laboratory of Water Cycle and Related Land Surface Process, institute of Geographical Sciences and Natural Resources Research, Chinese Academy of Sciences, Beijing 100101, china Renewable energy institute North China Electric Power University Beijing China Key Laboratory of Water Cycle and Related Land Surface Process Institute of Geographical Sciences and Natural Resources Research Chinese Academy of Sciences Beijing China

Transporting sediment is a natural function of the river. To maintain the normal evolution of the river certain amount of water flow is required, which is called the instream flow requirements for transporting sediment (IFRTS). We defined the permitting flow velocity by the conception of IFRTS, and also put forward the ecological hydraulic radius model (EHRM) to estimate IFRTS. The calculating process of EHRM is explained by the example of Daofu Hydrological Station on Xianshui branch of Yalong River in the west line first-stage construction of South-North Water Transfer Project. The result shows that the IFRTS occupied 29.7%―59.5% of annual mean discharge in flood season, the average of IFRTS was about 100.2 m3.s during 1966―1987, it is close to the IFRTS 90 m3.s calculated by IFRTS conception. Hence, it is feasible to use EHRM to calculate IFRTS.

关键词： ecological hydraulic radius model (EHRM) instream flow requirements for transporting sediment (IFRTS) permitting flow velocity ecological hydraulic radius for transporting sediment

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Chimney Effect Assessment of the Double-skin Facade

引用

湖南大学学报（自然科学版） 2009年第S1期36卷 146-150页

作者： QIU Zhong-zhu1,LI Peng2,CHOW Tin-tai3.REN Jian-xing1,WANG Wen-huan1(1.School of energy & Environment Engineering,Shanghai University of electric power,Shanghai 20090,{3. 2.School of Mechanical Engineering,Tongji University,Shanghai 200092,{3. 3.Division of Building Science & Technology,City University of Hong Kong,Hong Kong SAR,{3.) School of energy and Environment Engineering Shanghai University of Electric Power Shanghai 200090 China School of Mechanical Engineering Tongji University Shanghai 200092 China Division of Building Science and Technology City University of Hong Kong Hong Kong Hong Kong

The mathematic model of heat transfer through ventilated double glazing was verified with the measured data,which were from a test chamber equipped with glass face temperature,solar radiation,ambient temperature,and wind speed measurement *** the model validation,the double-skin facade assessment was carried out through simulation with ESP-r software integrating thermal simulation and air low net work *** air flow situation in the air gap was analyzed on the basis of the hourly air velocity simulation data within typical winter week,summer week,spring week and autumn *** differences of chimney effect in different seasons were discussed,and the thermal loads resulted from the ventilated and unventilated double skin facade were presented.

关键词： chimney effect assessment double-skin facade

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Partial discharge tests——at site for large power transformers

引用

electricity 1992年第3期 55-58页

作者： Wang Naiqing electric power Research institute,Ministry of {3.

*** obvious improvement in designing and manufacturingtransformers has been achieved since the application of partial dis-charge (PD) test on power transformers was *** Standard has stipulated that PD test is a routin... 详细信息

关键词： routine transformer designing brush otherwise installation terminals rubber saturated overload

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Comprehensive Refurbishment of 200 MW Thermal power Generating Units

引用

electricity 1997年第2期 26-30页

作者： Zhang Fuyin(Northeast china electric power Group Corp.)Shi Mingwu(Northeast china electric power Research institute)

This paper introduces the refurbishmentof 200 MW generating units in Northeastpower Network in recent years, to improvetheir operation reliability, economy,adjustability and controllability. It mainlydescribes the advanced technology used inimproving the combustion, optimizingpulverized coal distribution, economizerantiwear and strengthening heat transfer ofboiler sets and the refurbishment effects. Itintroduces technical measures and prot1ts inretro fit of flow passage of triple-flow lowpressure steam turbines, as well as theapplication of digital electronic hydraulic(DEH) govemors to realize the coordinatedcontrol and energy saving of generating units.(I) Refurbish ment of 200 MWBoiler Equipment in Northeastpower NetworkAbstractThis part introduces some measuresperformed to improve the operation level of2OO MW boiler sets of the power plants inNortheast power Network in recent *** the application of conce11trated(conc)-weak c0mbustion technology, theresearch and application of high-efficiencypulverized coal classifier, the application ofantiwear economizer and comprehensiveimprovement of insufficient temperature ofmain steam and reheated stean1. Afterrefurbishment the operating econo111y andsafety of the generating units are greatlyimproved.

关键词： boiler burner c1assifier economizer comprehensive improvement

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Analysis and application of the scale effect of flood discharge atomization model

引用

Science china(Technological Sciences) 2011年第S1期54卷 64-71页

作者： WU ShiQiang 1,WU XiuFeng 1,2,ZHOU Hui 1,CHEN HuiLing 1,SHA HaiFei 1 & ZHOU Jie 1 1 State Key Laboratory of Hydrology-Water resources and hydraulic Engineering,Nanjing hydraulic Research institute,Nanjing 210029,{3. 2 Hohai University,Nanjing 210098,{3. State Key Laboratory of Hydrology-Water resources and hydraulic Engineering Nanjing Hydraulic Research Institute Nanjing China Hohai University Nanjing China

The phenomenon of discharge atomization occurs as hydraulic structures discharging,which influences the safety of power station,electrical equipment and produces environmental pollution.A series of physical model {3.s and feedback analysis are adapted to preliminarily study the scale effect of discharge atomization model by use of the field observation data of discharge *** effect of Re and We numbers of flow on the atomization intensity is analyzed.A conversion relationship of atomization intensity between prototype and model results and the similarity criteria of the atomization range are developed. The conclusion is that the surface tension of discharge atomization model could be ignored when the Weber number is larger than *** case studies are given by use of the similitude criteria of the atomization model.

关键词： discharge atomization scale effect energy dissipation model test feedback analysis

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

NUMERICAL SIMULATIONS OF THE hydraulic CHARACTERISTICS OF SIDE INLET/OUTLETS

引用

Journal of Hydrodynamics 2011年第1期23卷 48-54页

作者： YE Fei GAO Xue-ping North china University of Water Conservancy and electric power Zhengzhou 450011 China School of Civil Engineering Tianjin University Tianjin 300072 China

The hydraulic characteristics at the side inlet/outlet of pumped storage plants is studied by numerical simulations,covering the flow distribution,head loss,vortex,and *** on the physical model test,the realizable k-εturbulence model is used in the 3.D simulation of the side inlet/outlet.A new scheme is suggested to obtain the uneven flow distribution over three branch *** variation of the free surface with the reservoir water level under the pumped condition is simulated,with results consistent with the experimental results.

关键词： hydraulic characteristics side inlet/outlet pumped storage plant numerical simulation realizable k-εturbulence model

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Time-Frequency Analysis Methods for power Quality Disturbances Feature Representation

Time-Frequency Analysis Methods for Power Quality Disturbanc...

引用

2010 International Conference on Advanced Measurement and test (AMT 2010)

作者： Lin Lin 1 a Jiajin Qi 2 b Nantian Huang 3.c and Shiguang Luo 4 d 1 College of Information and Control Engineering Jilin institute of Chemical Technology Jilin china 2 Hangzhou electric {3. Bureau State Grid Corporation of china Hangzhou china 3.department of electrical Engineering Harbin institute of Technology Harbin china 4 College of Computer Science and Technology Changchun University of Science and Technology Changchun china

power quality（PQ）analysis is the foundation of power system *** premise of power quality analysis is feature representation of power quality ***-frequency analysis （TFA）is very suitable for nonstationary signals *** TFA of a PQ signal is to determine the energy distribution along the frequency axis at each time *** paper provides a status report of feature representation for PQ events by TFA methods,including short time Fourier transform（STFT）, wavelet transform（WT）and S-transform（ST）,overview the basic TFA theories for PQ analysis and compare the effectiveness of different TFA *** expectation is that further research and applications of these TFA algorithms will flourish for PQ feature representation in the near future. The analysis direction and emphasis of studying are also put forward.

关键词： power quality(PQ) power quality disturbances time-frequency analysis(TFA) feature representation short time Fourier transform(STFT) wavelet transform(WT) S-transform(ST)

来源： cnki会议评论

在线全文

cnki会议

学校读者我要写书评

暂无评论

AN OPERATOR-SPLITTING ALGORITHM FOR ADVECTION-DIFFUSION-REACTION EQUATION

引用

Journal of Hydrodynamics 1992年第1期4卷 65-73页

作者： Cao Zhi-xian Wei Liang-yan Wuhan University of hydraulic and electric Engineering,Wuhan,Hubei 43.072,P.R.china

An operator-splitting algorithm for three-dimensional advection-diffusion-reaction equation is *** method of characteristics is adopted for the pure advection operator, the explicit difference scheme is used for diffusion,and a prediction-correction scheme is em- ployed for *** condition for stability of the algorithm is *** inear and nonlinear examples are illustrated to test the convergence and accuracy of the numerical proce- dure,and satisfactory agreements between computed and analytical solutions are *** to its simplicity,stability,and validity for both one-and two-dimensional problems,the success- ful algorithm can be used to numerical simulations of viscous fluid flows,the transport of pollu- tants and sedimentations in reservoirs,lakes,rivers,estuaries and other environments,cooling- problems in heat or nuclear power plants,etc.

关键词： advection diffusion fractional step method stability method of characteristies numerical dispersion oscillating solution

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

欢迎您,

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

请选择保存的检索档案：

请选择收藏分类：

通借通还

欢迎您,

建议与咨询 留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

请选择保存的检索档案： 新增检索档案 确定 取消

请选择收藏分类： 新增自定义分类 确定 取消

通借通还

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

请选择保存的检索档案：

请选择收藏分类：