九子溪电站水轮机增容改造

介绍了为九子溪电站水轮机增容研制的新型转轮。实际运行结果表明,在电站工况不变和未采取其他措施情况下,新转轮使原机组功率增容相对幅值达１５．３％。机组在不利的小负荷工况下运行近４０００ｈ,未见磨蚀痕迹,抗空蚀、抗磨蚀性能成于原转轮,新转轮完全可替代老的ＨＬ７０２型号水轮机转轮。     

HL240转轮改型设计与研究

本文运用近年来水轮机设计中取得的一些最新成果，结合新疆伊犁团结水电站混流式水轮机的增容改造，在不改变引水部件和尾水管的形状、参数及转轮与主轴联配关系的前提下，对转轮的上冠、下环型线及叶片进出口边的轴面投影进行了改型设计，应用三维流Ｓ２流面有旋流动的反问题计算重新设计了转轮。新转轮在１８ｍ水头下机组出力达１２５０ｋＷ，较原机组增大２５％，且运行平稳、振动小。     

Floating type ocean wave power station equipped with hydroelectric unit

The authors have invented the unique ocean wave power station,which is composed of the floating type platform with a pair of the floats lining up at the interval of one wave pitch and the counter-rotating type wave power unit,its runners are submerged in the seawater at the middle position of the platform.Such profiles make the flow velocity at the runner is twice faster than that of the traditional fixed/caisson type OWC,on the ideal flow conditions.Besides,the runners counter-rotate the inner and the outer armatures of the peculiar generator,respectively,and the relative rotational speed is also twice faster than the speed of the single runner/armature.Such characteristics make the runner diameter large,namely the output higher,as requested,because the torque of the power unit never act on the floating type platform.At the preliminary reseach,this paper verifies to get the power using a Wells type single runner installed in the model station.The runner takes the output which is affected by the oscillating amplitude of the platform,the rotational speed and the inertia force of the runner,etc.     

淮阴抽水站可逆式轴流泵装置性能研究

为了满足泵站抽水发电可逆运行的要求,应用Fluent软件,利用CFD数值模拟技术模拟了不同方案的流道内流场,分析了叶片翼型、叶片个数、轮毂比、导叶数量、导叶距转轮出口距离对水泵性能的影响,得到了最优的水力模型装置,即转轮叶片数为4、最优安放角为0°、轮毂比为0.40、导叶数为5、导叶进口边与转轮出口距离为268mm时,转轮具有更好的做功能力,且装置全流道效率和转轮效率达到最大值。根据数值模拟计算设计出的轴流式水泵水轮机转轮特性与模型试验结果比较接近,具备实际应用价值,不仅可节约新转轮的开发成本,且缩短了研发时间。     

张河湾抽蓄电站运行时过大厂房振动分析与处理

张河湾抽蓄电站装机4台250MW的抽水蓄能机组,机组投入运行后,一直存在过大的厂房振动和高频噪声,威胁了电站的安全稳定运行,影响了员工的身心健康。经测试分析和有限元计算,发现转轮与导叶间动静干涉而产生的压力脉动(无叶区压力脉动)造成局部厂房结构发生了共振现象。对转轮进行水力优化设计,转轮更换后,无叶区压力脉动大幅减小,2倍叶片过流频率分量幅值也大幅减小,随之厂房振动也大幅减小,高频噪声消失。厂房振动过大和高频噪声问题得到解决。研究成果可为其他抽蓄电站提供参考。     

基于流固耦合的某抽水蓄能电站可逆式水轮机转轮强度和模态分析

以国外某抽水蓄能电站为例,基于Ansys有限元计算平台,利用流固耦合方法研究了电站可逆式水轮机转轮在不同水头下机组流道内的水体对转轮叶片的影响,通过计算预应力和干湿条件下的转轮模态,分析了水体和预应力对转轮振动频率的影响。结果表明,在不同水头水压力作用下,转轮的静应力最大值出现在上冠与叶片相连处,叶片最大变形出现在叶片出水边的中间位置,且随着水头的升高而增大;预应力对转轮模态的影响较小,而水介质因阻尼作用对转轮模态减小效果明显。     

基于流固耦合的某抽水蓄能电站可逆式水轮机转轮强度和模态分析

以国外某抽水蓄能电站为例,基于Ansys有限元计算平台,利用流固耦合方法研究了电站可逆式水轮机转轮在不同水头下机组流道内的水体对转轮叶片的影响,通过计算预应力和干湿条件下的转轮模态,分析了水体和预应力对转轮振动频率的影响。结果表明,在不同水头水压力作用下,转轮的静应力最大值出现在上冠与叶片相连处,叶片最大变形出现在叶片出水边的中间位置,且随着水头的升高而增大;预应力对转轮模态的影响较小,而水介质因阻尼作用对转轮模态减小效果明显。     

某可逆式机组厂房振动问题的原因分析及处理方案

针对某电站存在的厂房振动问题,首先开展了机组稳定性试验,找出了厂房振动的激振振源,通过有限元分析法得出厂房内存在局部振动区域的结论,并找出局部共振的位置,最后提出了优化转轮的解决方案。新转轮经过一年时间运行,稳定性各项指标均在正常范围内,证明了所提供方案的有效性。     

基于流固耦合的混流式水轮机转轮裂纹改造分析

为了解光照电厂转轮裂纹的改造效果,借助ANSYS有限元计算平台,利用流固耦合方法分析转轮改造前后在不同水头、负荷下的流场及动、静应力。计算结果表明,转轮在叶片出口边中部有较大变形,应力集中点在叶片出口边靠近上冠与下环处,与现场发现的裂纹位置相同,说明应力集中是裂纹出现的原因之一。转轮上冠、下环与叶片出水边连接处加装三角块对转轮的水力性能影响可忽略;而转轮最大应力降幅均超过20%,最大应力位置从连接处转移至三角块处,可有效改善转轮裂纹情况。     

不对称二重叶栅对水轮机性能影响的探讨

对某水电站D75—35型水轮机的蜗壳、固定导叶、活动导叶内部的流动进行了解析计算，结果表明：受固定导叶不对称分布的影响，固定导叶和活动导叶内部的压力和速度分布不均匀，尾流较为明显，能量损失较大；压力和速度的脉动变化以及不均匀分布进一步延伸至转轮，将会造成转轮运行的不稳定，进而影响整个水轮机组的稳定运行。     

Performance assessment of a small wind turbine with crossflow runner by numerical simulations

Most of the classical wind turbines are not able to start at wind speeds as low as 2–3 m/s. Other turbines, like Savonius, have a low maximum efficiency, which renders them useless in poor wind conditions. Therefore, new turbine designs are required to harvest wind power even when the wind speed is low. A wind turbine having a crossflow runner, similar to the Banki water turbine, is studied numerically in this work in order to estimate its performance. The results obtained suggest that this turbine has a considerable high starting torque and its maximum power coefficient is comparable to those of horizontal axis wind turbines. Based on the results obtained, some improvements of the design are proposed in order to further increase turbine performance.     

导叶开度对混流式水轮机转轮内部流态的影响

基于数值模拟方法,以梯级水光蓄互补联合发电系统示范工程中的猛固桥电站混流式水轮机为研究对象,对水轮机在不同特征水头、不同导叶开度工况下转轮叶片表面受力及流道内流场特性进行研究,分析导叶开度改变对水轮机转轮内流态的影响规律。结果表明：导叶开度对于混流式转轮进口流态的影响较大,导叶开度越小入流速度波动程度越大,来流对叶片头部冲击越大,在进口处产生严重的冲击损失;随导叶开度减小,转轮叶片表面等压线与进口边夹角增大,在上冠交接区域产生小三角区低压,使转轮流道出口更易产生空化损失。     

间隙模拟技术在贯流水轮机数值分析中的应用

介绍了间隙模拟技术,应用间隙模拟技术模拟桨叶轮缘与轮毂间隙的实际形状,并对贯流式水轮机桨叶间隙流动进行了模拟数值计算.以某电站为例,对电站转轮水力性能进行了数值计算和分析.与实况比较表明,间隙模拟技术能有效模拟内流道流动,并能准确计算协联工况点.     

基于CFD混流式水轮机上冠转轮泵结构优化研究

为研究中高水头混流式水轮机上冠转轮泵工作特性及优化可行性,以红山嘴一级电站3号水轮机为例,建立现转轮泵及11种结构优化模型,利用CFD商业软件,基于SST湍流模型对不同结构转轮泵在9种流量工况下展开数值模拟。将上冠流道泄漏水流动特性、主轴密封真空度及转轮泵效率作为研究指标,结果表明：上冠流道泄漏水流动特性依赖于转轮泵的结构类型;减小转轮泵“泵盖高度比”或斜置动泵叶对提高主轴密封真空度均有显著效果(最佳结构可提高66.9%),同时须兼顾其工作效率;额定工况下,转轮泵工作效率较低,建议转轮上冠开设合适的泄水孔补给流量提高其效率;该电站可将泵叶斜置45°、泵盖高度比H_p=0.0543的转轮泵作为最佳改进方案。     

轴流式转轮叶片水力设计CAD系统

为提高轴流式转轮叶片水力设计的精度和速度,开发出水力设计CAD系统.介绍了开发工具的选取及开发思路、软件系统各模块的主要功能及其关系;针对某电站具体水力参数给出了用开发的CAD软件设计叶片的实例.结果表明：方法正确可行,编制的CAD软件可靠、快速、准确、界面友好.     

小木岭二级站顶盖压力过高的成因分析及技改措施

针对小木岭二级水电站高水头混流式机组顶盖水压过高的问题,通过对机组实际运行数据和转轮结构的分析并结合理论分析,提出了改变转轮上冠止漏环型式并适当减小止漏环间隙以增强止水效果的技术改造方案,结果表明技改方案是成功的。     

汽轮机结构元件的损伤和寿命评估

提出了汽轮机转子在高应力疲劳与高温蠕变变互作用下的损伤本构模型与寿命评估方法,以及用于汽轮机转子结构分析的基本方程与变分原理,利用“间置加载”型荷载谱的特点,提出两个基本假设,并根据初始循环应力应变场对损过程中的循环应力应变场进行了有效描述,可对汽轮机转子结构寿命进行评估。     

多工况下高水头水泵水轮机压力脉动特性分析

为研究多工况下高水头水泵水轮机内部的压力脉动特性,以某抽水蓄能电站水泵水轮机模型为例,采用SST湍流模型对非设计工况点下的水泵水轮机进行三维全流道非定常数值模拟,同时监测了固定导叶与活动导叶间、无叶区及尾水管处的压力脉动。结果表明,对于固定导叶与活动导叶之间的区域,水轮机工况下的压力脉动主频为叶片通过频率,而水泵工况下的最高扬程和最低扬程工况的主频分别为转频和叶片数通过的频率;对于无叶区,由于受到强烈的动静干涉效应,水轮机、水泵工况下的主频均为转轮叶片数通过频率,且脉动幅值较大;对于尾水管区域,直锥段处的频率分布规律与流量有关,水轮机小流量工况下,尾水管内主要为0.3倍转频的低频压力脉动,而水轮机大流量工况下,脉动频率主要以2.6倍转频为主。     

Experimental investigation of the influence of blade height and blade number on the performance of low head axial flow turbines

Investigations regarding the influence of design parameters in low head axial flow turbines like blade profiles, blade height and blade number for micro-hydro application continue to be inadequate, even though there is a need and potential for the application of such turbines. This inadequacy provides a good ground to make a detailed experimental study to characterize these influences.The paper presents a holistic theoretical model that attempts to bring out a functionality of the internal performance parameters of the runner and attempts to establish a physical relationship between the two design parameters (blade height and blade number) and the performance parameters.The experimental results on 3 runners showed that with an increase in the number of blades, the efficiency of the runner dropped drastically due to the change in direction of the relative flow vector at the runner exit, which decreased the net rotational momentum and increased the axial flow velocity. The decrease of blade height on the other hand decreased the overall runner loss coefficient quite drastically but this could not result in major performance gains.The study concluded that the influence of blade number is more dominating compared to that of the blade height and that choice of blade number should be carefully made. On the hydraulic level, the study found interesting effects like the slip phenomenon and loss mechanisms within the runner. The paper also looks into the possible errors within the theoretical model developed and the extent of their influence on the conclusions. The paper suggests more experimental studies to separately study the effects of blade number and blade height. It further makes a strong case to initiate a computational work to validate all the experimental findings, fill the gaps in the theoretical model and use it as an optimization and standardization tool for axial flow turbines in the specialized application of micro-hydro.     

高水头电站水轮机沙水流动特性的数值研究

研究泥沙磨损有助于降低水轮机磨损,延长水轮机使用寿命。运用Partical两相流模型对高水头多泥沙电站的水轮机全流道内部沙水两相流动进行数值计算,并分别分析转轮进口沿叶高20%、50%、80%流面的流动特性。计算结果表明,压力从固定导叶进口到转轮出口圆周方向的周向性较好,分布合理,最低压力高于空化压力。活动导叶上泥沙相体积分数最高在导叶头部位置,尾部泥沙相体积分数也较高,导叶靠近头部处和导叶尾部泥沙速度最大。转轮叶片各叶高流面泥沙相体积分数均在叶片工作面尾部达到最大,叶片头部和尾部位置泥沙速度均较高。研究结果对水轮机选材、关键磨损部位的预测及防护方案具有指导意义。