涡轮机叶片磨损测量技术试验研究

1前言涡轮机叶片的磨损直接影响涡轮机的性能、可靠性和寿命。船用燃气轮机叶片涂层磨损后,叶片的基体材料在燃气轮机高温烟气产生的近1 000℃的环境中所引起的高温腐蚀和高温蠕变会严重影响机组的可靠性和寿命。船用汽轮机工作在高湿度蒸汽中的叶片,长期受水滴的高速冲蚀,极易     

风沙环境下风力机叶片冲蚀磨损的数值研究

基于N-S方程,结合RNG k-ε湍流模型和DPM模型对风沙环境下风轮的冲蚀磨损行为进行数值计算。通过分析不同颗粒直径和浓度下风轮的冲蚀磨损特性,研究风沙对风力机叶片冲蚀磨损的主要部位,以及叶片磨损与颗粒粒径和沙尘浓度的关系。研究发现,叶片磨损最严重的区域位于叶片前缘部分,次严重区域为叶片压力面;颗粒粒径对叶片磨损区域和磨损速率的大小影响显著;颗粒浓度对磨损位置影响很小,叶片的磨损速率随着颗粒浓度的增加呈线性规律增加。     

风力机叶片涂层风沙冲蚀磨损特性的风洞试验研究

传统的挟沙冲蚀试验台与风沙风洞难以构建均匀风沙流场,难以准确反映风力机叶片的风沙磨损特性。因此,在改造的风沙风洞中,通过对风力机叶片平板试样开展涂层冲蚀磨损试验,探究不同冲击速度、冲击角度及有效截面质量流率对风力机叶片涂层材料冲蚀特性的影响规律。试验结果表明：有效颗粒质量流率一定时,在相同冲击速度与冲击时间内,磨损量在冲击角度约为30°时达到最大。小于30°时,磨损量随冲击角度的增大而快速增加,大于30°时磨损量随冲击角度的增大而逐渐降低;磨损量随冲击速度的增大而增大;磨损量随有效颗粒质量流率的增大而呈线性增大趋势;切削磨损量与总磨损量有相同趋势,冲击磨损量随着冲击角度的增大而逐渐增大。     

带粒气流对透平叶片冲蚀特性的数值分析与试验研究

基于欧拉－拉格朗日解基本思想，数值模拟了带粒双级跨音速燃气透平三元粘性湍流场，在此基础上以计入颗粒湍流扩散的颗粒随机轨道模型和PSIC法实现了气固双向耦合，跟踪和分析了10万个分布直径和石英砂、催化剂颗粒的运动轨迹及颗粒滑移程度，并计算了叶片的质量冲蚀率。结果表明：涂层后叶片的质量冲蚀率较基体可减小一个数量级。另外，分别采用石英砂和催化剂颗粒对2Cr12Mo－5基体材料和MCrAlY涂层进行了冲蚀试验，通过比较发现：在大部会冲击角下，涂层能有效地减小叶片的冲蚀；在同样的试验条件下，大石英砂颗粒造成的叶片冲蚀强于小石英砂颗粒。     

含尘流透平叶片涂层的气动冲蚀行为

从气运冲蚀的角度,对在喷砂型固体颗粒冲蚀试验装置上使用石英砂颗粒和催化剂果粒对长城1号涂层叶片进行了有关涂层冲蚀行为的试验,根据试验结果讨论了冲击速度的冲击角度对涂层冲蚀率的影响;此外,就颗粒的种类、形状和尺寸对涂层冲蚀率的影响进行了探讨。     

风力机叶片涂层风蚀过程的有限元分析

利用有限元瞬态动力学方法分析了单个球形二氧化硅粒子对叶片聚氨酯涂层的冲蚀过程。数值模拟结果表明,涂层表面的冲蚀坑以及唇口断裂损伤与实际环境中受到的损伤特征非常接近,聚氨酯涂层在90°冲蚀角度下的耐冲蚀性能强于45°冲蚀角度下的耐冲蚀性能;风速垂直分量的大小以及涂层与颗粒接触时间是涂层微观结构发生屈服的主要因素;冲击载荷应力以波的形式在结构内传播,与数值模拟动态显示下的应力传播相一致。     

电站锅炉管道高温冲蚀磨损和涂层防护技术分析

在锅炉的实际运行过程中,由于高温环境,锅炉会出现冲蚀磨损问题,其安全性也就会随之下降,这就需要通过涂层防护技术来加以保护。本文就是对其管道高温冲蚀磨损问题和涂层防护技术进行分析,希望可以对当今电站锅炉的正常应用提供出更好的依据。     

挟沙风对风力发电机叶片冲蚀磨损的数值研究

风力发电机叶片的风沙冲蚀问题是风电机组耐候性研究的重点之一,该文通过数值模拟的方法,基于1.5 MW的叶片,建立相似模型,研究不同沙尘粒径、不同来流风速和不同叶尖攻角等冲蚀条件对叶片的磨损特性及规律。研究表明：叶片受到的磨蚀率随风速增大而增加,在9 m/s风速时冲蚀分布集中于叶根、叶尖附近,随着风速增大冲蚀由叶根向叶片的中后段移动,且冲蚀效果更显著;随着沙粒粒径增大,叶片磨蚀率逐渐增大,且集中在叶根和叶片中前段;风沙冲蚀角度影响叶片表面的冲蚀分布,角度越大,冲蚀分布的面积越大。     

固体废弃物循环流化床焚烧惯性分离器涂层材料抗磨损试验研究

采用循环流化床焚烧固体废弃物已成为一种有效的方法.而分离装置是循环流化床燃烧的关键部件之一,在炉膛出口布置惯性分离器可有效分离飞灰,实现物料循环.惯性分离器处于高温、高含尘浓度的工作环境中,因此要求其制备材料具有很强的抗磨损性能.文章选取0Cr13作基材,施加耐磨涂层,通过热态磨损试验研究了两种涂层材料的抗磨损性能.100h试验后结果表明:1号涂层的抗磨损性能要优于2号;高温区所受到的磨损和冲蚀要比低温区严重;涂层施加得愈平整、效果愈好,则其抗磨损性能愈好;涂层中的高铬含量有效增强了涂层抗磨损的能力.     

呼图壁储气库气井冲蚀规律初探

对于地下储气库而言,由于强注强采,高速流动的气体对管柱产生的冲蚀磨损是影响气井管柱寿命的重要因素。针对气井冲蚀问题,研究了材料冲蚀的不同内在机理,包括微切削理论、基于单点冲蚀的切削模型、锻造挤压理论、变形磨损理论、二次冲蚀理论和弹塑性压痕破裂理论。结合呼图壁储气库气井实际管柱结构与生产状况,认为微切削理论和变形磨损理论是主要的冲蚀破坏机理,并指出了管柱和井下工具不同部位所适用的不同的破坏机理。分析了造成气井冲蚀的影响因素,主要包括粒子的冲蚀角度、冲蚀速度、粒度、砂粒含量以及材料的硬度、弹性模量、类型、腐蚀对冲蚀的影响、环境温度等,并针对呼图壁储气库的实际情况,提出了减少甚至避免气井冲蚀的具体防护措施。呼图壁储气库优选的改良型13Cr气井管柱,具有良好的耐冲蚀性能。     

Leading edge erosion of coated wind turbine blades: Review of coating life models

Erosion of the leading edge of wind turbine blades by droplet impingement wear, reduces blade aerodynamic efficiency and power output. Eventually, it compromises the integrity of blade surfaces. Elastomeric coatings are currently used for erosion resistance, yet the life of such coatings cannot be predicted accurately. This review paper gives an overview of experimentally validated erosion model blocks that can be used to predict the life of the leading edge of coated wind turbine blades. From the reviewed work it is concluded that surface fatigue, as nucleating wear mechanism for erosion damage, can explain erosive wear and failure of the coatings. An engineering approach to surface fatigue, using the Palmgren–Miner rule for cumulative damage, allows for the construction of a rain erosion incubation period equation. Coating life was described as a function of the rain intensity, the droplet diameter, the fatigue properties of the coating and the severity of the conditions. It is recommended to focus coating development on reduction of the impact pressure, e.g. by developing surfaces with a low modulus of elasticity; or on enlarging the safe area by: developing coatings with adjustable compressive stresses and hardness, or coatings without defects and impurities.     

Wind turbine blade coating leading edge rain erosion model: Development and validation

This paper applies existing research to develop an analytical surface fatigue model to predict the initiation of leading edge erosion on wind turbine blade coatings due to rainfall. We have used rain erosion whirling arm tests to determine the surface impact fatigue resistance of different coatings used in the field. The analytic model has been validated to predict the initiation of wind turbine leading edge erosion by using a large data base of photos of leading edge erosion observations taken from wind farms in multiple countries, offshore, and onshore. The aerodynamic impact of the erosion has also been modeled and been used to determine the expected sectional efficiency loss of the damaged airfoils. Combining the leading edge erosion forecast model with the efficiency reduction model, we can predict annual energy production loss over time on different sites due to rain‐induced wind turbine blade coating leading edge erosion.     

Non-destructive and contactless defect detection inside leading edge coatings for wind turbine blades using mid-infrared optical coherence tomography

Leading edge erosion of wind turbine blades is one of the most critical issues in wind energy production, resulting in lower efficiency, as well as increased maintenance costs and downtime. Erosion is initiated by impacts from rain droplets and other atmospheric particles, so to protect the blades, special protective coatings are applied to increase their lifetime without adding significantly to the weight or friction of the blade. These coatings should ideally absorb and distribute the force away from the point of impact; however, microscopic defects, such as bubbles, reduce the mechanical performance of the coating, leading to cracks and eventually erosion. In this work, mid-infrared (MIR) Optical Coherence Tomography (OCT) is investigated for non-destructive, contactless inspection of coated glass-fiber composite samples to identify subsurface coating defects. The samples were tested using rubber projectiles to simulate rain droplet and particle impacts. The samples were subsequently imaged using OCT, optical microscopy, and X-ray tomography. OCT scanning revealed both bubbles and cracks below the surface, which would not have been detected using ultrasonic or similar non-destructive methods. In this way, OCT can complement the existing quality control in turbine blade manufacturing, help improve the blade lifetime, and reduce the environmental impact from erosion.     

风电机组叶片表面阻燃涂层材料的研制

当风电机组叶片所处的工作环境中发生火灾事故时,涂在叶片表面的阻燃涂层可阻止火源将燃烧传递至叶片,或减缓叶片燃烧的趋势。本项研究是在现有风电机组叶片的原有结构特殊部位的基础上增加阻燃涂层,将火源与叶片隔离,有效防止叶片延续燃烧现象,达到延长叶片使用寿命为目的。     

Erosion modelling on reconstructed rough surfaces of wind turbine blades

Numerical simulations of rain droplet impacts on real rough surfaces of leading edges of wind turbine blades are presented. The effect of rough blade surface conditions during liquid impacts on the stress distribution in the protective coating is studied. Realistic rough surfaces of wind turbine blades, obtained from 3D reconstruction of real blades with photogrammetry, as well as artificially generated rough surfaces were introduced into finite element models of the droplet/blade coating interaction. Stress distributions in the protective coating with rough and flat surfaces were studied and compared. The results of the simulations suggest that roughness on the surface of the blade leads to increased stresses in the protective coating.     

Quantification of wind turbine energy loss due to leading-edge erosion through infrared-camera imaging,numerical simulations,and assessment against SCADA and meteorological data

Quantification of the performance degradation on the annual energy production (AEP) of a wind farm due to leading-edge (LE) erosion of wind turbine blades is important to design cost-effective maintenance plans and timely blade retrofit. In this work, the effects of LE erosion on horizontal axis wind turbines are quantified using infrared (IR) thermographic imaging of turbine blades, as well as meteorological and SCADA data. The average AEP loss of turbines with LE erosion is estimated from SCADA and meteorological data to be between 3% and 8% of the expected power capture. The impact of LE erosion on the average power capture of the turbines is found to be higher at lower hub-height wind speeds (peak around 50% of the turbine rated wind speed) and at lower turbulence intensity of the incoming wind associated with stable atmospheric conditions. The effect of LE erosion is investigated with IR thermography to identify the laminar to turbulent transition (LTT) position over the airfoils of the turbine blades. Reduction in the laminar flow region of about 85% and 87% on average in the suction and pressure sides, respectively, is observed for the airfoils of the investigated turbines with LE erosion. Using the observed LTT locations over the airfoils and the geometry of the blade, an average AEP loss of about 3.7% is calculated with blade element momentum simulations, which is found to be comparable with the magnitude of AEP loss estimated through the SCADA data.