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Power fluctuation and power loss of wind turbines due to wind shear and tower shadow

Binrong WEN, Sha WEI, Kexiang WEI, Wenxian YANG, Zhike PENG, Fulei CHU

《机械工程前沿（英文）》 2017年 第12卷 第3期   页码 321-332 doi: 10.1007/s11465-017-0434-1

摘要：

The magnitude and stability of power output are two key indices of wind turbines. This study investigates the effects of wind shear and tower shadow on power output in terms of power fluctuation and power loss to estimate the capacity and quality of the power generated by a wind turbine. First, wind speed models, particularly the wind shear model and the tower shadow model, are described in detail. The widely accepted tower shadow model is modified in view of the cone-shaped towers of modern large-scale wind turbines. Power fluctuation and power loss due to wind shear and tower shadow are analyzed by performing theoretical calculations and case analysis within the framework of a modified version of blade element momentum theory. Results indicate that power fluctuation is mainly caused by tower shadow, whereas power loss is primarily induced by wind shear. Under steady wind conditions, power loss can be divided into wind farm loss and rotor loss. Wind farm loss is constant at 3α(3α−1)R2/(8H2). By contrast, rotor loss is strongly influenced by the wind turbine control strategies and wind speed. That is, when the wind speed is measured in a region where a variable-speed controller works, the rotor loss stabilizes around zero, but when the wind speed is measured in a region where the blade pitch controller works, the rotor loss increases as the wind speed intensifies. The results of this study can serve as a reference for accurate power estimation and strategy development to mitigate the fluctuations in aerodynamic loads and power output due to wind shear and tower shadow.

关键词： wind turbine     wind shear     tower shadow     power fluctuation     power loss    

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A novel light fluctuation spectrum method for in-line particle sizing

Shouxuan QIN, Xiaoshu CAI, Li MA

《能源前沿（英文）》 2012年 第6卷 第1期   页码 89-97 doi: 10.1007/s11708-012-0176-z

摘要： This paper discusses two problems in in-line particle sizing when using light fluctuation method. First, by retrieving the ratio of particle concentrations at different time, the intensity of incident light is obtained. There exists narrow error between the calculated and pre-detected value of the intensity of incident light. Secondly, by combining spectrum analysis with Gregory’s theory, a multi-sub-size zone model is proposed, with which the relationship between the distribution of turbidity and the particle size distribution (PSD) can be established, and an algorithm developed to determine the distribution of turbidity. Experiments conducted in the laboratory indicate that the measured size distribution of pulverized coal conforms well with the imaging result.

关键词： in-line measurement     particle size distribution (PSD)     incident light intensity     particle concentration     light fluctuation    

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基于同步波动原理的抗冲蚀弹性涂层设计

郭源君,肖华林,徐大清,李文斌

《中国工程科学》 2008年 第10卷 第9期   页码 60-63

摘要：

基于过流面冲蚀波纹形貌特征与流体边界层扰动波参数的对应关系，提出了实现弹性涂层边壁与边界层扰动波的同步波动，从而变边壁被动承受粒子冲击为主动回避与粒子的碰撞的抗冲蚀设计思想；分析了实现弹性涂层边壁与边界层扰动波同步波动的条件，并由此确定出弹性涂层的材料常数。

关键词： 冲蚀     边界层     弹性边壁     弹性涂层     同步波动    

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Optimal portfolio design of energy storage devices with financial and physical right market

《能源前沿（英文）》 2022年 第16卷 第1期   页码 95-104 doi: 10.1007/s11708-021-0788-2

摘要： With the continuous development of the spot market, in the multi-stage power market environment with the day-ahead market and right market, the study associated with the portfolio of energy storage devices requires that attention should be paid to transmission congestion and power congestion. To maximize the profit of energy storage and avoid the imbalance of power supply and consumption and the risk of node price fluctuation caused by transmission congestion, this paper presents a portfolio strategy of energy storage devices with financial/physical contracts. First, the concepts of financial/physical transmission rights and financial/physical storage rights are proposed. Then, the portfolio models of financial contract and physical contract are established with the conditional value-at-risk to measure the risks. Finally, the portfolio models are verified through the test data of the Pennsylvania-New Jersey-Maryland (PJM) electric power spot market, and the comparison between the risk aversion of portfolios based on financial/physical contract with the portfolio of the market without rights. The simulation results show that the portfolio models proposed in this paper can effectively avoid the risk of market price fluctuations.

关键词： portfolio     node price fluctuation     transmission right     energy storage right     risk aversion    

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Numerical simulation and analysis of periodically oscillating pressure characteristics of inviscid flow in a rolling pipe

Yan GU, Yonglin JU

《能源前沿（英文）》 2012年 第6卷 第1期   页码 21-28 doi: 10.1007/s11708-012-0173-2

摘要： Floating liquefied natural gas (LNG) plants are gaining increasing attention in offshore energy exploitation. The effects of the periodically oscillatory motion on the fluid flow in all processes on the offshore plant are very complicated and require detailed thermodynamic and hydrodynamic analyses. In this paper, numerical simulations are conducted by computational fluid dynamics (CFD) code combined with user defined function (UDF) in order to understand the periodically oscillating pressure characteristics of inviscid flow in the rolling pipe. The computational model of the circular pipe flow is established with the excitated rolling motion, at the excitated frequencies of 1–4 rad/s, and the excitated amplitudes of 3°–15°, respectively. The influences of flow velocities and excitated conditions on pressure characteristics, including mean pressure, frequency and amplitude are systematically investigated. It is found that the pressure fluctuation of the inviscid flow remains almost constant at different flow velocities. The amplitude of the pressure fluctuation increases with the increasing of the excitated amplitude, and decreases with the increasing of the excitated frequency. It is also found that the period of the pressure fluctuation varies with the excitated frequency. Furthermore, theoretical analyses of the flow in the rolling circular pipe are conducted and the results are found in qualitative agreement with the numerical simulations.

关键词： pressure fluctuation     rolling     floating production storage and offloading unit for liquefied natural gas (LNG-FPSO) offshore    

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A novel high-temperature and high-pressure hydraulic pump based on mononeuron control

Linhui ZHAO, Xin FANG

《机械工程前沿（英文）》 2009年 第4卷 第2期   页码 219-223 doi: 10.1007/s11465-009-0024-y

摘要： Based on structures and characteristics of traditional hydraulic pumps, this paper proposes a novel high-temperature and high-pressure hydraulic pump (HHHP) that can work under 150°C and 28 MPa to overcome problems of traditional high-temperature plunger pumps. The HHHP is designed with the structure of mechanical division and double cylinder parallel. The control signals of two cylinders are two separate triangle waveforms with 90° phase difference. Because the output waveforms of two cylinders have the same characteristics as the control signals, the HHHP can obtain a stable output after two separate waveforms are superposed. A mononeuron self-adaptive PID control algorithm is also improved by modifying parameters and . Two improved controllers are used to control the two cylinders, respectively, making two displacements of plungers match each other. Therefore, reduced fluctuations and stable pressure output is obtained. Besides simulation, tests on the built prototype test system are carried out to verify the performance of HHHP. Results show that the improved control approach can limit fluctuations to a lower level and the HHHP system attains good outputs under different signal periods and different pressures.

关键词： mononeuron PID control     hydraulic pump     pressure fluctuation    

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Distribution, characteristics and daily fluctuations of microplastics throughout wastewater treatment plants with mixed domestic–industrial influents in Wuxi City, China

《环境科学与工程前沿（英文）》 2022年 第16卷 第1期   页码 6-6 doi: 10.1007/s11783-021-1440-4

摘要：

• MPs were analyzed throughout three WWTPs with mixed domestic–industrial influents.

关键词： Microplastic     Wastewater treatment plant     Mixed domestic-industrial influent     Characteristic     Daily fluctuation    

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Removal of pharmaceutical and personal care products by sequential ultraviolet and ozonation process in a full-scale wastewater treatment plant

Qian SUI, Jun HUANG, Shuguang LU, Shubo DENG, Bin WANG, Wentao ZHAO, Zhaofu QIU, Gang YU

《环境科学与工程前沿（英文）》 2014年 第8卷 第1期   页码 62-68 doi: 10.1007/s11783-013-0518-z

摘要： The application of appropriate advanced treatment process in the municipal wastewater treatment plants (WWTPs) has become an important issue considering the elimination of emerging contaminants, such as pharmaceutical and personal care products (PPCPs). In the present study, the removal of 13 PPCPs belonging to different therapeutic classes by the sequential ultraviolet (UV) and ozonation process in a full-scale WWTP in Beijing was investigated over the course of ten months. Most of the target PPCPs were effectively removed, and the median removal efficiencies of individual PPCPs, ranging from -13% to 89%, were dependent on their reaction rate constants with molecular ozone. Noticeable fluctuation in the removal efficiencies of the same PPCPs was observed in different sampling campaigns. Nevertheless, the sequential UV and ozonation process still made a significant contribution to the total elimination of most PPCPs in the full-scale WWTP, by compensating for the poor or fluctuant removal performance of PPCPs by biologic treatment process.

关键词： PPCPs     advanced treatment     ozone     fluctuation     removal contribution    

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Numerical simulation of sudden-expansion two-phase flows with two-scale second-order moment particle turbulence model

ZENG Zhuoxiong, HAN Shoulei, ZHOU Lixing

《能源前沿（英文）》 2007年 第1卷 第2期   页码 202-206 doi: 10.1007/s11708-007-0026-6

摘要： A two-scale second-order moment particle turbulence model is developed, based on the concept of particle large-scale fluctuation due to turbulence and particle small-scale fluctuation due to collision. The model is employed to simulate gas-particle flows in a sudden-expansion chamber. Simulation results are compared with the experimental results and with those obtained by the single-scale second-order moment two-phase turbulence model. It is shown that the two-scale model is with higher calculating accuracy than the single-scale model.

关键词： gas-particle     single-scale second-order     large-scale fluctuation     second-order     sudden-expansion    

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Three-dimensional fluorescence spectral characterization of soil dissolved organic matters in the fluctuating water-level zone of Kai County, Three Gorges Reservoir

Fang FANG, Yan YANG, Jinsong GUO, Hong ZHOU, Chuan FU, Zhe LI

《环境科学与工程前沿（英文）》 2011年 第5卷 第3期   页码 426-434 doi: 10.1007/s11783-010-0264-4

摘要： Three-dimensional fluorescence spectroscopy was used to investigate the fluorescent properties of soil dissolved organic matter (DOM) in the water-level-fluctuation zone (WLFZ) of Kai County, Three Gorges Reservoir (TGR). Most of the soil DOM analyzed in this study was found to contain four fluorescence peaks. Peaks A and C represent humic-like fluorescence, whereas peaks B and D represent tryptophan-like fluorescence. Peaks E and F, which represent tyrosine-like fluorescence, only appeared in certain soils. Soil humus was the main source of DOM in soil, and higher concentration of soil DOM was found in the exposed soil than submerged soil. Compared to the peaks A and B, the fluorescence intensities of peaks C and D were strongly influenced by the fluctuating water level. Analysis of fluorescence intensities of different peaks in soil DOM showed that WLFZ soil was not contaminated significantly. Soil DOM contained at least two types of humic-like fluorescence groups and two types of protein-like fluorescence groups. The proportion of the content of peak A in soil organic matter was quite stable. The soil DOM in exposed soil had relatively high humification and aromaticity, and periodic submerging and exposure of soil had an impact on the humification of soil DOM.

关键词： water-level-fluctuation zone (WLFZ)     soil     dissolved organic matter (DOM)     three-dimensional fluorescence spectra    

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标题 作者 时间 类型 操作

Power fluctuation and power loss of wind turbines due to wind shear and tower shadow

Binrong WEN, Sha WEI, Kexiang WEI, Wenxian YANG, Zhike PENG, Fulei CHU

期刊论文

A novel light fluctuation spectrum method for in-line particle sizing

Shouxuan QIN, Xiaoshu CAI, Li MA

期刊论文

基于同步波动原理的抗冲蚀弹性涂层设计

郭源君,肖华林,徐大清,李文斌

期刊论文

Optimal portfolio design of energy storage devices with financial and physical right market

期刊论文

Numerical simulation and analysis of periodically oscillating pressure characteristics of inviscid flow in a rolling pipe

Yan GU, Yonglin JU

期刊论文

A novel high-temperature and high-pressure hydraulic pump based on mononeuron control

Linhui ZHAO, Xin FANG

期刊论文

Distribution, characteristics and daily fluctuations of microplastics throughout wastewater treatment plants with mixed domestic–industrial influents in Wuxi City, China

期刊论文

Removal of pharmaceutical and personal care products by sequential ultraviolet and ozonation process in a full-scale wastewater treatment plant

Qian SUI, Jun HUANG, Shuguang LU, Shubo DENG, Bin WANG, Wentao ZHAO, Zhaofu QIU, Gang YU

期刊论文

Numerical simulation of sudden-expansion two-phase flows with two-scale second-order moment particle turbulence model

ZENG Zhuoxiong, HAN Shoulei, ZHOU Lixing

期刊论文

Three-dimensional fluorescence spectral characterization of soil dissolved organic matters in the fluctuating water-level zone of Kai County, Three Gorges Reservoir

Fang FANG, Yan YANG, Jinsong GUO, Hong ZHOU, Chuan FU, Zhe LI

期刊论文