Videometric research on deformation measurement of large-scale wind turbine blades

Utilization of wind energy is a promising way to generate power,and wind turbine blades play a key role in collecting the wind energy effectively.This paper attempts to measure the deformation parameter of wind turbine blades in mechanics experiments using a videometric method. In view that the blades experience small buckling deformation and large integral deformation simultaneously, we proposed a parallel network measurement(PNM) method including the key techniques such as camera network construction,camera calibration,distortion correction,the semi-automatic high-precision extraction of targets,coordinate systems unification,and bundle adjustment,etc. The relatively convenient construction method of the measuring system can provide an abundant measuring content,a wide measuring range and post processing.The experimental results show that the accuracy of the integral deformation measurement is higher than 0.5 mm and that of the buckling deformation measurement higher than 0.1mm.

Experimental study of rotating wind turbine breakdown characteristics in large scale air gaps

When a wind turbine is struck by lightning,its blades are usually rotating.The effect of blade rotation on a turbine＇s ability to trigger a lightning strike is unclear.Therefore,an arching electrode was used in a wind turbine lightning discharge test to investigate the difference in lightning triggering ability when blades are rotating and stationary.A negative polarity switching waveform of 250/2500 μs was applied to the arching electrode and the up-and-down method was used to calculate the 50%discharge voltage.Lightning discharge tests of a 1：30 scale wind turbine model with 2,4,and 6 m air gaps were performed and the discharge process was observed.The experimental results demonstrated that when a 2 m air gap was used,the breakdown voltage increased as the blade speed was increased,but when the gap length was 4 m or longer,the trend was reversed and the breakdown voltage decreased.The analysis revealed that the rotation of the blades changes the charge distribution in the blade-tip region,promotes upward leader development on the blade tip,and decreases the breakdown voltage.Thus,the blade rotation of a wind turbine increases its ability to trigger lightning strikes.

A Very Large Scale Wind Turbine

A very large scale wind turbine can be made as a circular large scale stator frame;the frame,which can reach some kilometers in diameter and some hundred meters in height,contains many circular sail trains.The stator frame can be made using a light-weight tubular design.Wind can almost freely blow through this frame.Train rails are fixed at the outer surface of the frame as horizontal rings.The distance between the rails of one ring can be made to be several meters.As a result,the number of the rings can be ten or more.Each rail ring supports one sail train that is moved with wind power around the frame.The energy of this movement is transformed to electric power and is transmitted to the base of the frame.This design can be realized in a very large scale,which is difficult to achieve using a traditional three-blade turbine.

Decentralized Stabilization of Large-scale Uncertain Systems with State-Delays——LMIs Approach

This paper deals with the problem of decentralized robustcontrol for a class of interconnected uncertain systemswith state delays.The parameter uncertainties are un-known but norm-bounded.A new sufficient condition isobtained for each subsystem and overall system to be sta-bilizable via linear memoryless state feedback robust de-centralized controllers.The results depend on the size of the delays and are given in terms of linear matrix ine-qualities,so they are less conservative than those of delay-independent.Moreover,matching condition is not a necessary condition.Finally,an example is presented to illustrative the effectiveness of the proposed method.

Utilization Survey of Livestock Manure Resources in Large-scale Farms of Yangzhou

Based on surveying the conditions of large -scale farms and commercial manure in the each county of Yangzhou city, the situations and problems for utilization of livestock manure resources were grasped. After an analysis of the potential value of livestock manure, the suggestion and strategy for utilization of livestock manure resources were proposed based on the actual conditions in Yangzhou city.

Formation conditions and exploration direction of large natural gas reservoirs in the oil-prone Bohai Bay Basin, East China

The Bohai Bay Basin is a typical oil-prone basin, in which natural gas geological reserves have a small proportion. In this basin, the gas source rock is largely medium-deep lake mudstone with oil-prone type Ⅱ2-Ⅱ1 kerogens, and natural gas preservation conditions are poor due to active late tectonic movements. The formation conditions of large natural gas fields in the Bohai Bay Basin have been elusive. Based on the exploration results of Bohai Bay Basin and comparison with large gas fields in China and abroad, the formation conditions of conventional large-scale natural gas reservoirs in the Bohai Bay Basin were examined from accumulation dynamics, structure and sedimentation. The results show that the formation conditions of conventional large natural gas reservoirs in Bohai Bay Basin mainly include one core element and two key elements. The core factor is the strong sealing of Paleogene "quilt-like" overpressure mudstone. The two key factors include the rapid maturation and high-intensity gas generation of source rock in the late stage and large scale reservoir. On this basis, large-scale nature gas accumulation models in the Bohai Bay Basin have been worked out, including regional overpressure mudstone enriching model, local overpressure mudstone depleting model, sand-rich sedimentary subsag depleting model and late strongly-developed fault depleting model. It is found that Bozhong sag, northern Liaozhong sag and Banqiao sag have favorable conditions for the formation of large-scale natural gas reservoirs, and are worth exploring. The study results have important guidance for exploration of large scale natural gas reservoirs in the Bohai Bay Basin.

极端运行阵风对15 MW风力机叶片结构性能影响的分析

基于CFD方法,对极端运行阵风条件下IEA Wind 15 MW水平轴风力机气动性能进行分析。采用ANSYS APDL软件定义复合材料铺层方案建立15 MW风力机叶片有限元模型,并基于Workbench平台对风力机叶片进行模态分析和静力学分析,研究极端运行阵风对风力机叶片结构性能的影响。结果显示:极端运行阵风对风力机气动性能和叶片结构性能影响较大,风轮推力与转矩极值出现的时间点均迟于风速极值点,沿叶片展向叶片流动分离区域与风速呈正相关;在极端运行阵风期间,叶片位移均是从叶根至叶尖逐渐增大,叶片最大应力出现在叶片主梁并且距叶根0.6 R处,同时,由于叶片的叶尖位移和最大应力在短时间内大幅度变化,会使叶片破坏的概率增加。

陆上风电碳足迹动态变化的国际比较研究

碳中和目标下国际风电产业将继续扩大规模,碳市场、碳关税等国际气候减排政策工具也在不断完善,未来可再生能源碳足迹对相关产业成本与发展将产生重要影响。本文以中国、欧洲、美国等风电产业优势国家和地区作为研究对象,构建陆上风电系统生命周期评价过程、生命周期清单,完成相关地区陆上风电碳足迹的参数比较并总结变化趋势,进一步分析趋势成因并阐明影响因素。结果表明,在风力机大型化加速、发电效率提高、工业生产清洁化的态势下,2011—2022年世界优势地区的陆上风电碳足迹均呈下降趋势,中国、欧洲、美国的平均降幅分别为49.2%、46.2%、20.8%,相应下降量均集中在设备生产阶段;中国已将碳足迹下降至与欧洲接近的水平,与美国的差距缩减到3.63 g/kW·h,其中工业生产清洁化水平不高、风机容量因子偏低分别是中国陆上风电碳足迹高于欧洲、美国的主要原因。中国在推进风电产业发展的过程中,需着重提高风电系统发电效率、加快改善产业清洁化生产水平、支持风电系统退役回收产业发展,以稳步降低陆上风电系统生命周期内的碳足迹。

大型风力机塔架-叶片体系风振与地震作用对比研究

为研究风荷载和地震作用对大型风力机不同部件的影响程度,建立某3 MW水平轴风力机塔架-叶片一体化有限元模型,通过CFD数值模拟获得风力机表面风压系数并作为风荷载输入参数,同时进行7度地震烈度作用下的反应谱分析。对比研究表明:叶片受风荷载控制,其在风荷载作用下的叶尖位移和叶根弯矩均明显大于地震作用下的数值;塔架由风荷载和地震作用共同控制,风荷载作用下弯矩值均沿高度方向逐渐增加,地震作用下径向与环向弯矩最大值出现在接近塔顶高度处;风荷载作用下塔底环向弯矩及径向与环向轴力均明显大于地震作用,但地震作用下塔底径向和竖向弯矩及剪力稍大于风荷载作用下的数值。

多变气热参数下大尺度槽深叶顶的流动换热特性

为了研究具有渐缩型面凹槽在不同深度下叶顶间隙的流动换热特性,针对某一级高压涡轮,在发动机五种典型工况下通过改变其凹槽深度,采用k-ω湍流模型以及自适应湍流模拟方法(SATES)分别进行定常和非定常的数值仿真分析。研究结果表明,凹槽深度是影响间隙泄漏流动和叶顶换热特性的重要因素,同时该影响趋势也受涡轮工作状态的限制。相比于深凹槽,浅凹槽方案的间隙泄漏量明显降低,对应的涡轮动叶出口总压损失系数也有所降低,这在涡轮小流量状态时尤为明显。然而,深凹槽设计在降低叶顶热负荷方面表现更好,其中槽深0.8H方案比槽深0.1H方案的叶顶平均努塞尔数降低38.3%~95.3%。定常和非定常两种计算方法主要影响了间隙内局部泄漏量和叶顶前部热负荷的预测值,并未改变流动换热特性的分布趋势。

基于改进融合的大型风力发电机组运行状态检测研究

为解决传统的大型风力发电机设备运行状态检测方法效果不佳的问题,设计了基于多特征融合的大型风力发电机设备运行状态检测方法。通过计算提取出的运行状态数据集的多个数据特征,并计算不同特征的权重值,实现数据的多特征融合,并对其进行特征分类。通过计算运行状态数据的偏离阈值和检测阈值,完成对设备运行状态的检测。实验结果表明,和以往的大型风力发电机设备运行状态检测方法相比,设计的基于多特征融合的大型风力发电机设备运行状态检测方法在实际应用中ROC曲线面积较大,检测效果较好。

电厂大型汽轮机双压凝汽器运行自适应优化研究

【目的】由于双压凝汽器的高、低压双侧压力在实际运行时和预先设计值之间存在较大差距,影响凝汽器的运行效益,因此提出电厂大型汽轮机双压凝汽器运行自适应优化研究。【方法】首先基于双压凝汽器真空度的影响参数的历史运行数据,引入灰色理论,构建一个电厂大型汽轮机双压凝汽器真空计算模型,将各影响参数代入模型中,即可输出未来时刻的双压凝汽器真空度预测计算值。然后以凝汽器最佳真空度精确控制为目标,利用粒子群算法寻找模型最优超参数。最后将最优超参数应用于双压凝汽器的真空运行中,实现自适应优化。【结果】研究结果表明,设计方法优化后的双压凝汽器循环水流量明显低于优化前,在1.2×10^(-4) kg/s~1.4×10^(-4) kg/s之间。【结论】该研究结果可以提高机组的运行效率和稳定性,有助于提升电厂大型汽轮机的节能运行效益。

大型机组汽轮机本体节能改造

随着能源与环境问题的日益突出,节能改造成为了工业领域的重要议题。大型机组汽轮机作为关键能源转换设备,其本体节能改造对于提高能源利用效率,降低运营成本及减少环境污染具有重要意义。文章针对大型机组汽轮机本体节能改造进行了分析,结果表明,通过大型机组汽轮机本体的节能改造,可提高能源利用效率,降低能耗和排放,达到节能减排的目标。

大型风电叶片模具绿色制造与服役关键技术

从绿色设计、绿色工艺、绿色服役3个方面系统探讨了大型风电叶片模具绿色制造的关键技术,重点研究了模具轻量化设计、环保材料应用、智能化加工、表面强化处理、再制造等方面的新理念、新技术、新方法,为风电产业的健康可持续发展提供有力的装备技术支撑。

西门子V94.3A型燃气-蒸汽联合循环机组冷态启动及优化

分析西门子V94.3A型燃气-蒸汽联合循环机组的冷态启动过程中碰到的问题和现象,讨论了减少冷态启动时间、提高冷态启动安全性、优化冷态启动过程的方法。

中国海上风电发展现状及展望

海上风电是中国加快能源转型进程,助力“双碳”目标早日实现的重要战略支撑。2022年中国海上风电正式进入平价时期,但在补贴取消、需求透支等因素影响下,海上风电市场经历短期低谷。在梳理后补贴时代中国海上风电发展现状的基础上,分析了新增装机容量、招标数量、技术创新、风机价格等方面的新变化。最后,结合行业发展现状与能源发展“十四五”规划要求,预测未来几年中国海上风电建设成本将进一步下降、行业将迎来新一波的建设高峰。

大型风电机组气动计算相似模型构建

受早期新能源产业技术发展制约,许多处于运营期后期的风电机组的各个部件出现不同程度的老化情况,运行状况呈现逐年下降趋势。此时需要对风电机组进行建模计算以进一步对其各部件进行分析。对风机进行建立模型时,通常会遇到机组设计参数缺失的现象,尤其是风电叶片的气动外形部分。通过相似参考参数将风电机组气动性能与叶片气动布局相关联,构建一种大型风电机组叶片气动计算相似模型。与目标机组模型各项气动参数对比发现,构建的相似机组模型在风能利用系数、气动转矩、气动功率方面很好地反映了目标机组性能。

大容量海上风电机组故障穿越电磁暂态模型辨识方法

现有的电磁暂态建模方法多针对小容量机组在典型电压跌落工况的模拟,缺乏同时对不同运行点和不同电压扰动工况的全面模拟和验证。基于某大容量海上风电机组的“黑盒”模型,通过主电路和控制电路模型辨识及模型验证,提出了其白盒化电磁暂态建模方法。针对主电路,辨识出了由典型半直驱旋转系统、中性点钳位的并联三电平变流器和保护电路模块组成的大容量全功率型机组的主电路拓扑及参数。针对控制电路,辨识出了中性点电位平衡控制器及其稳态、对称和不对称电压跌落/升高情况下的控制器和参数。通过与实际机组在不同运行点和不同电压扰动下的故障穿越全过程响应特性的对比发现,所建立暂态模型的响应特性与实际机组一致,证明了该建模方法的有效性。

AN ADAPTIVE CONTROL STRATEGY FOR PROPER MESH DISTRI-BUTION IN LARGE EDDY SIMULATION

The Filtering Grid Scale （FGS） of sub-grid scale models does not match with the theoretical Proper FGS （PFGS） because of the improper mesh. Therefore, proper Large Eddy Simulation （LES） Mesh is very decisive for better results and more economical cost. In this work, the purpose is to provide an adaptive control strategy for proper LES mesh with turbulence theory and CFD methods. A new expression of PFGS is proposed on the basis of -5/3 law of inertial sub-range and the proper mesh of LES can be built directly from the adjustment of RANS mesh. A benchmark of the backward facing step flow at Re = 5147 is provided for application and verification. There are three kinds of mesh sizes, including the RANS mesh, LAM （LES of adaptive-control mesh）, LFM （LES of fine mesh）, employed here. The grid number of LAM is smaller than those of LFM evidently, and the results of LAM are in a good agreement with those of DNS and experiments. It is revealed that the results of LAM are very close to those of LFM. The conclusions provide positive evidences for the novel strategy.

大型水轮发电机组A级检修(改造)本质安全设施的探索与实践

大型水轮发电机组A级检修(改造)涉及到机组固定部件、中心、转轮室空蚀、磁极、线棒绝缘、定子转子圆度等进行维护检修,针对机组拆、装检修各作业点无人身安全防护系统和专用检修平台的隐患,摒弃传统脚手架等方式,探索运用了快装式新型航空铝材专用检修平台和水平防坠系统等安全设施,以科技手段确保水轮发电机组A修(改造)的安全高效。