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为了得到某燃气轮机涡轮叶片关键截面的真实寿命,设计并开展了涡轮叶片热-机械疲劳试验,获得了真实寿命数据,并基于试验结果提出了一种涡轮叶片低周疲劳与蠕变疲劳交互的寿命预测方法。首先,采用一维线弹性关系、修正公式以及循环应力应变关系3种名义应力应变处理模型计算获得了名义应变;然后,利用SWT寿命关系式预测模型预测了叶片的热-机械疲劳寿命;再将预测寿命与试验获得的真实寿命进行对比分析。研究表明:对于某型燃气轮机涡轮叶片,基于SWT预测模型的循环应力应变关系方法相比于一维线弹性关系和修正公式法预测精度最高,与试验寿命相比,预测误差在4倍分散带之内。 相似文献
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本文在金属材料典型蠕变过程的基础上,分别研究了蠕变各个阶段的本构模型。针对金属材料在较高应力下没有蠕变稳定阶段的现象,提出了金属材料高低应力值的判定准则并根据高低应力的不同特点推导了不同的耦合损伤本构模型。通过对舰用燃气轮机涡轮叶片材料的蠕变试验结果与模型预测结果进行比较可以看出:本文提出的蠕变模型近似地模拟金属材料的蠕变全过程,准确地预测金属材料的蠕变寿命。 相似文献
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电站锅炉高温受压部件的结构强度安全性,一直是电站锅炉设计人员十分关注的问题。由于高温部件除承受工质内压外,尚需承受温度荷载,破坏失效机理比较复杂。本文对锅炉高温部件蠕变疲劳分析现状,锅炉高温部件的破坏型式及应力控制原则,影响锅炉高温寿命的主要因素进行了分析,提出了工程上比较现实的处理方法。对其分析研究发展进行了探讨。 相似文献
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《热力透平》2021,50(3)
透平叶片是燃气轮机寿命设计的关键部件,其内部复杂的冷却结构直接影响甚至制约透平叶片的低周疲劳寿命。为此,针对某型燃气轮机透平静叶中的内部扰流结构,基于整体模型的分析结果,应用子模型方法构建局部分析模型,通过对比边界路径上的应力结果确定用于优化设计的基准模型方案,最后分析了3种不同倒圆半径方案的应力和低周疲劳寿命,并与初始方案结果进行对比,结果表明随着扰流柱倒圆半径的增大,应力水平明显降低,低周疲劳寿命次数显著提升。同时,应用子模型方法对复杂模型的单个结构特征进行优化设计,得到的计算精度和效率比整体模型更高。研究成果能够为燃气轮机透平叶片结构设计分析提供指导。 相似文献
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风力机玻璃钢叶片疲劳寿命分析 总被引:4,自引:0,他引:4
该文对大型风力机玻璃钢叶片疲劳寿命的工程估算方法进行了研究。运用片条理论分析了影响风力机叶片疲劳寿命的气动载荷分布;根据有限元模态叠加法,计算了叶片在气动力、重力和旋转惯性力等确定性载荷作用下的动态应力响应;介绍了玻璃钢材料的疲劳破坏过程、破坏准则,探讨了玻璃钢材料疲劳性能及疲劳寿命估计方法;最后,运用Palmgren Miner的线性疲劳损伤累积法则提出了一种玻璃钢叶片安全寿命估计方法。通过所设计的1.5兆瓦变速变桨距风力机叶片疲劳寿命估计的算例表明,本文提出的玻璃钢叶片疲劳寿命估计方法是可靠和实用的。 相似文献
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建立了燃气轮机高温涡轮叶片损伤评估模型,包括热力学性能计算模型、应力评估模型、热评估模型和交互损伤分析模型,无法测量参数由热力学性能计算模型计算,作为应力评估模型和热评估模型的输入。根据蠕变与疲劳损伤模型分析结果,对进气道内使用喷雾冷却降温的燃气轮机高温涡轮叶片进行损伤评估,比较了燃气轮机在不同转速以及负荷下,使用喷雾冷却系统前后,高温涡轮叶片损伤的变化,定量评估喷水量对高温叶片寿命的改善。结果表明:启用喷雾冷却系统可以大幅减小因蠕变造成的叶片损伤,在低负荷(30%)时损伤减小的幅度尤为明显,其预期寿命从40 000 h延长到50 000 h以上,可以大幅延长叶片的使用寿命;在夏季运行时(53%负荷),如果以减少蠕变损伤为目标,可以考虑增加喷水量,从40%~100%,叶片各级蠕变损伤最高可减小13.5%。 相似文献
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Florian Sayer Falko Bürkner Benjamin Buchholz Michael Strobel Arno M. van Wingerde Hans‐Gerd Busmann Henry Seifert 《风能》2013,16(2):163-174
This paper presents results out of investigations of the DEBRA‐25 wind turbine blades. Almost unique in the history of modern wind energy, these blades were in operation for 18 years next to a weather station and were investigated afterward. Therefore, the loads experienced in the operational life could be post‐processed accurately with the measured data of the weather station and the turbine. The blades are made of materials that are similar with today's wind turbines. Furthermore, intensive laboratory tests and free field tests have been carried out, and all load assumptions and data and results are still available today. The results include experimental investigations on the moisture content of the load‐carrying material, static and fatigue behavior of the material, the relaxation of the coupling joints, the natural frequencies of the blade and a full scale static blade test. It is shown that the structural performance of the DEBRA‐25 service blades is comparable with modern wind turbine blades. Although some damage was found by visual inspection, the service blade of the DEBRA‐25 showed excellent mechanical behavior in the full scale blade test. Only small changes of the edgewise eigenfrequencies were detected. The pre‐tensioning forces of the IKEA bolts, where the two blade parts are connected, were measured and were still adequate. Copyright © 2012 John Wiley & Sons, Ltd. 相似文献
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This study aims to develop a fatigue life prediction method and to identify the effect that a 10-minute mean wind speed distribution has on the fatigue life of a small-scale wind turbine composite blade. First, combining the von Karman isotropic turbulence model and the Weibull distribution for a 10-minute mean wind speed provided us with the 1-Hz full wind history for a specific time period. Accordingly, the fatigue stress spectra at the blade's fatigue-critical locations (FCLs) were created by applying a stress tensor, in which the interaction between flapwise and edgewise bending moments was taken into consideration. The fatigue life of a composite blade can be predicted with a reliability R = 95% by applying the P–S–N curve obtained from the constant amplitude fatigue tests and rainflow cycle counting, and cumulative damage rule to the fatigue stress spectra. To acquire the second-order regression equation, nonlinear regression analysis was performed on the fatigue lives, which were simulated by using the proposed fatigue life prediction method. In this equation, the variables were the shape parameter, K, and the scale parameter, C, of the Weibull distribution for a 10-minute mean wind speed. The effects of the Weibull parameters on fatigue life were evaluated through the sensitivity analysis of the equations. 相似文献
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Asger Bech Abrahamsen Justine Beauson Kristine Wilhelm Lund Erik Skov Madsen David Philipp Rudolph Jonas Pagh Jensen 《风能》2024,27(2):165-178
A model of the evolution of the onshore wind turbine blade mass installed in Denmark is proposed described by a Weibull distribution, and the age of the blades is estimated from decommissioning data to = 29 years when half of the blade mass of an installation year has been decommissioned. This is considerably longer than the 20 year design lifetime of onshore turbines, which is often assumed to be an estimate of the End-of-Life of turbine blades. Thus, blade waste predictions using the simple assumption may predict that installed blade masses are entering recycling processes about 9 years sooner that what is observed in Denmark. The blade mass for decommissioning in Denmark is estimated to peak at 2000 and 5000 ton/year in 2028 and 2045 using the Weibull model. 相似文献
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Starting from the first steam injection cycles (GE‐STIG; Cheng), the technique of increasing gas turbine performances by injecting water/steam somewhere before the combustion chamber, has shown very interesting results for power and efficiency increase and for NOx emissions. Very interesting performances are achieved by evaporative cycles, such as the HAT (Humid Air Turbine), which is capable of achieving 50% conversion efficiency with lower investment costs compared to combined cycles. Other advantages of the steam injected cycle include the power modulation that is possible by varying the injected steam flow rate, keeping the maximum temperature constant. In particular, for the HAT cycle, it is possible to choose different temperature, pressure and compositions for the blade cooling fluid, depending on the bleed point. In this paper, a second law analysis of the HAT cycle and its components, has been performed. In particular, the exergetic analysis of blade cooling has been carefully analysed. Copyright © 1999 John Wiley & Sons, Ltd. 相似文献
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Fatigue testing of a 48.3 m wind turbine blade needs to utilize the blade's oscillation range of 8.4 m along the flapwise direction for one million cycles. Control of such a remarkable oscillation range makes flapwise fatigue testing difficult and requires a large supply of energy. This study minimized the actuating force required for flapwise fatigue testing using an on‐board‐type resonance exciter with constant amplitude. Constraints related to the exciter's stroke and capacity and the maximum error between target loads and test loads were also considered. Based on a new algorithm suggested in this study, first, we found test setup candidates minimizing the maximum error under a given testing frequency and then found more candidates having slightly larger maximum errors as the exciter's location moved toward the blade's tip. Next, using damping ratio equations for the test blade, a required actuating force of the exciter at each test setup candidate was calculated. Considering the exciter's capacity, we found an optimum test setup that requires a minimum actuating force in the vicinity of the minimum of the maximum error between target loads and test loads. To conclude, the approach suggested in this study was able to conclusively achieve the required fatigue testing of the test blade, avoiding the adverse increase of fatigue testing time possible to happen due to a required actuating force larger than the exciter's capacity. Copyright © 2015 John Wiley & Sons, Ltd. 相似文献
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为提高某型燃气轮机的工作可靠性,对单晶涡轮叶片进行了强度分析与结构优化设计。采用第四强度理论,考虑了晶体取向、温度载荷、气动载荷和转速的影响,得到叶片的应力分布、典型截面的强度储备系数;根据诺顿蠕变方程计算关键节点的持久寿命;基于分析结果对叶片局部结构进行优化改进,将叶片质心向叶背侧偏移,调整进气前缘气膜孔的排列方式,并对新结构进行强度复算。结果表明:优化后的叶片静强度符合设计要求,消除了局部结构处的应力集中现象,叶身结构强度储备系数高于1.3,叶身两侧应力分布更加均匀,叶片在设计转速10%裕度范围内无共振现象发生。 相似文献