大中型风力发电机组可靠性研究

研究了大中型风力发电机组的可靠性，讨论了可靠性指标的分配，可靠性设计的四个重要方面、可靠性试验计算机模拟。     

机组油膜振荡故障的诊断和处理

通过对广州发电厂1号机组3号轴承突发剧烈振动的现象和测试结果的分析，对振动故障进行诊断并提出解决办法，对3号轴承轴瓦进行处理后，机组恢复正常运行状态。     

尾流受扰下复杂体形高层建筑的风压分布特性

本文结合汕头粤东信息大厦的风洞试验,详细分析了复杂结构断面建筑物在其尾流受到下游结构干扰下的风压分布特性。试验表明:处于受扰物体尾流边界上的施扰物体可以降低来流在受扰物体上的分离速度,从而使最大负压系数降低。当施扰物体处于被扰物体尾流边界的某些位置时,被扰物体表面的最大负压系数受到显著影响,最多可降低45%。文中还对典型断面结构进行了进一步的试验研究,在验证以上的结论同时,试验结果也显示,施扰建筑位于被扰结构临近的较大区域,其风压增大15%以上,最大可增大39%。本文所得的一些结论可为相应的工程提供参考。     

河北省张承地区风沙现状及治理对策

在分析张家口、承德地区风沙形成原因及发展趋势的基础上,提出了河北省防沙治沙工作中存在的问题,根据河北省不同类型区的自然、地理及社会经济条件,提出了风沙治理模式和建议。     

激光测风雷达二维扫描控制系统的实现

二维扫描系统使得激光出射方向和光学接收光轴同时精确指向设定方向,进而测量多方位的风速数据。介绍了激光测风雷达二维扫描控制系统组成,重点讨论了系统运用步进电机进行驱动的电路特点以及采取的可靠性技术措施,包括硬件措施和软件措施,分析了该系统的先进性、可靠性以及智能化特点。该控制系统已经成功地安装在中国科学院安徽光机所的激光测风雷达上,经过了一年半的实际运行,其控制精度、运行速度完全满足激光测风雷达的测量要求。     

水库水面蒸发量计算方法的研究

根据水库水面蒸发机制，结合前人研究成果，提出一种新的水库水面蒸发量计算模型，利用不同气候区多站资料确定模型参数，并利用全国各地30多个水库漂浮蒸发站实验资料，对模型进行拟合检验与移用检验，结果表明，该模型的适应性很强，有推广前景。对模型特性较深入的分析说明，该模型较过去常用的几种模型有许多更合理之处。     

An analytical expression for the power coefficient of an ideal horizontal-axis wind turbine

The paper shows that an analytical evaluation of the power coefficient C_p for an ideal horizontal-axis wind turbine can be made via an expression giving the direct relationship of C_p and the axial induction factor a. The results obtained agree closely with those obtained numerically from the usual integral expression involving several variables.     

Reduction of low-frequency pressure fluctuations in wind tunnels

The determination of dynamic wind loads on buildings, i.e. pressure and deflection, has gained increasing interest (European Prestandard ENV 1991-2-4, Eurocode 1: basis of design and actions on structures—Part 2-4: actions on structures—wind actions, European Committe for Standardization, Brussels, 1995; DIN 1055 Teil 4 Lastannahmen für Bauten, Verkehrslasten, Windlasten bei nicht schwingungsanfälligen Bauwerken, 1991; N. Hölscher, M. Hortmanns, J. Sahlem, Praxisnahe Erfassung von Windwirkung an Industrie- und Hochbauten, Windwirkung im Bauwesen, Braunschweig, 7, Dreiländertagung D-A-CH 2001, Windtechnologische Gesselschaft, 2001 [1], [2] and [3]). Therefore, the spectral distributions of velocity and pressure fluctuations in wind tunnels are an important quality aspect. While velocity fluctuations can be manipulated by the obstacles used to create the turbulence, pressure fluctuations are influenced by acoustic noise as well. Especially, the first eigenfrequency of the longitudinal mode of the wind tunnel tends to disturb the pressure spectrum.In this paper, a solution for the reduction of low-frequency acoustic pressure fluctuation is presented and its application in the atmospheric boundary layer wind tunnel at the IAG is shown.     

Analysis of lightning surge propagation in wind farm

Wind power generation is expected to become more important in future distribution systems. Although several prospective reports such as IEC 61400‐24 and NREL SR‐500‐31115 indicate an insulation scheme and grounding design for lighting protection, there still seems to be too few investigations on the problems. This paper therefore discusses lightning surge analysis using a wind farm model with 2 or 10 ideal wind turbines. Changing parameters such as grounding resistance and lightning strike points, several cases were studied. As a result of the analysis using digital simulator ARENE, it is clear that the surge tends to propagate toward the end of a distribution line in a wind farm and there is the possibility of insulation accidents at the other wind turbines when lightning attacks a wind turbine. © 2007 Wiley Periodicals, Inc. Electr Eng Jpn, 162(2): 30– 38, 2008; Published online in Wiley InterScience ( www.interscience.wiley.com ). DOI 10.1002/eej.20364     

非定常流弯肘型尾水管不规则压力脉动预测

尾水管内螺旋状涡带引起的压力脉动是造成混流式水轮机机组振动的主要原因之一,直接威胁机组的安全运行。为此,提出一种基于CFD数值计算的水轮机尾水管压力脉动数字化预测法,并利用此法对一大型混流式水轮机偏工况下尾水管内水流流动进行了长时间非定常流计算,讨论该工况下尾水管内死水域与涡带的运动规律,预测了尾水管的不规则压力脉动,压力脉动分析结果表明,其波形、频率、相位与实际基本一致。