共查询到19条相似文献,搜索用时 250 毫秒
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《中国工程机械学报》2017,(3)
风电机组运行在低温、高湿的环境中,叶片往往会出现结冰现象.叶片覆冰后改变了叶片原有翼型形状且影响叶片的固有频率,进而影响风电机组的载荷特性.抗冰冻机组从安全性设计角度考虑低温环境下叶片覆冰对风电机组载荷的影响.以某2MW陆上抗冰冻机组为研究对象,采用GH Bladed软件建立风电机组模型,结合特定环境条件考虑均匀覆冰、不均匀覆冰以及低温环境中不同空气密度对风电机组极限载荷的影响,统计风电机组关键部件中叶片、轮毂、塔架上的载荷,分析叶片覆冰前后风电机组关键部件极限载荷变化情况,为抗冰冻机组的设计优化提供参考. 相似文献
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《机械工程与自动化》2017,(1)
利用ANSYS有限元软件建立了大型风力发电机组塔架的有限元分析模型,分别进行了塔架的静强度和模态分析,计算出了塔架的固有频率和模态振型以及塔架在极限载荷下的应力和塔顶的位移。结果表明:该塔架结构满足强度要求,且风力发电机组在运行过程中不会与塔架发生共振,从而为今后塔架进一步的优化分析设计提供依据。 相似文献
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塔架是风电机组中最为重要的承载部件,为验证塔门部位结构的合理性,采用有限元软件Hyper Mesh对塔门部位实体模型进行规则的网格划分,并对其进行强度分析。分析结果表明,在各极限载荷工况下,塔门部位的最大应力值均小于材料的许用应力,能够达到最初的设计要求。同时分析也为开发相关系列产品提供了可靠数据。 相似文献
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塔架作为风力发电机组的主要承载部件,其性能直接影响风力机的使用寿命与安全,因此对塔架结构进行优化设计尤为重要.以2 MW风力发电机组塔架为研究对象,以塔架质量为优化目标,固频、应力、高度等为约束条件,直径、壁厚和节长为控制变量,通过仿真对塔架进行结构优化,并通过解析求解对仿真进行校核.结果表明,优化设计的塔架不仅减轻了塔架重量4.21%,同时提高了固有频率,避开了共振区间;仿真法与解析法结果对比,应力最大位置一致,解析应力比仿真小22.3%,解析模态一阶模态比仿真大18%,仿真具有一定的可信度;该优化方法具有一定的实用性和工程应用价值,适合推广应用. 相似文献
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针对风电机组设计如何避免耦合共振的问题,采用拉格朗日方法,建立了风轮动力学方程和塔架耦合系统动力学方程,联立获得了风电耦合系统动力学方程,以市场成熟的1 500 k W变速变桨双馈机组为研究对象,解耦获得了系统模态参数。然后展开了现场实测工作,挑选云南某风电场1 500 k W机组,实测了风轮系统和塔架耦合系统模态数据,进行了数据分析,研究了风电系统整机运行稳定性。研究结果表明:理论模型及各子系统边界连接条件简化方式符合现场实际情况,最大偏差为8.6%,具有较高的精准性,该理论模型可为兆瓦级风电机组研发、设计和优化提供理论指导依据。 相似文献
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Moo Yeol Park Seockhyun Kim Insu Paek Chengxun Cui 《Journal of Mechanical Science and Technology》2013,27(6):1731-1737
This study considers the prediction of natural frequency to avoid resonance in a wind turbine tower-cable coupled system. An analytical model based on the Rayleigh-Ritz method is proposed to predict the resonance frequency of a wind turbine tower structure supported by four guy cables. To verify the validity of the analytical model, a small tower-cable model is manufactured and tested. The frequency and mode data of the tower model are obtained by modal testing and finite element analysis. The validity of the proposed method is verified through the comparison of the frequency analysis results. Finally, using a parametric study with the analytical model, we identified how the cable tension and cable angle affect the resonance frequency of the wind turbine tower structure. From the analysis results, the tension limit and optimal angle of the cable are identified. 相似文献
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The identification technique of output-only modal parameters is proposed for the large wind turbine tower under emergency stop. Compared with the response of regular operating conditions, the immediate tower structural response under emergency stop much more resembles a state of free vibration, which is more appropriate for the modal identification of the wind turbine tower. The vibration response is measured in the nacelle, which is easy to perform in the field modal test. The variational mode decomposition (VMD) is applied to decompose the vibration response into several band-limited intrinsic mode functions. The free responses of decomposed functions are extracted by applying the random decrement technique (RDT). Finally, the modal damping ratio and natural frequency are identified from each free modal response by using the Hilbert transform method. Simulations and a 1.5 MW wind turbine field modal test results verify the effectiveness of the proposed identification method. The main modal parameters of wind turbine, including weak modes, are effectively extracted by using output-only vibration responses under emergency stop. The modal parameter identification method is provided for the large wind turbine structure under the engineering condition. 相似文献
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现有冷却塔结构自振频率主要基于有限元分析手段,缺乏简单有效的冷却塔自振频率估算公式。为解决该问题,以国内某179m高的大型冷却塔为基准塔,首先,通过改变结构典型参数(塔高、喉部高度、喉部直径、进风口高度和支柱截面积)获得基准塔的38个模型并进行动力特性分析,同时提炼出基频和倾覆频率随结构参数的变化规律;然后,用扰动法和拉丁超立方抽样(Latin hypercube sampling,简称LHS)两种方法进行结构自振频率参数的敏感性分析,获取了不同阶数下各参数的敏感因子,在此基础上,创新性地拟合提出考虑敏感因子权重值的多参数基频和倾覆频率的实用估算公式;最后,验证自振频率估算公式的精度,选择课题组已有研究的冷却塔进行了误差分析。揭示结构参数对大型冷却塔自振频率的敏感性具有重要意义,可为冷却塔结构抗风抗震设计、动力特性优化设计等提供指导。 相似文献
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基于有限元法的风力发电机塔架模态分析 总被引:1,自引:0,他引:1
针对某大型风力发电机组,通过ANSYS有限元软件对其建立有限元模型,对风力发电机塔架进行模态分析,确定其固有频率和振型,比较塔架的固有频率与风轮的工作频率或风轮3倍的工作频率之间的相对差,计算结果表明,塔架为刚性塔,不会与风轮产生共振,且弯曲振动为塔架的主要振动形式,为作进一步的动态分析提供了理论依据。 相似文献
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针对大型风力机运行中塔架常见的倾斜、中间凸出、焊缝开裂等故障,利用ANSYS有限元分析软件和工程算法对其结构进行了动力特性、屈曲分析和焊缝的分析。通过塔架模态分析可以优化塔架设计,避免风机在正常工作时塔架与风轮发生共振;屈曲和焊缝分析能够保证塔架的刚度和强度满足极限工况的负荷要求,从而为塔架的结构设计提供最佳参数依据。 相似文献
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运用有限元分析软件ANSYS10.0对风力发电机锥筒式钢塔架进行非线性静强度分析,得到了额定发电、切出风速和极限风速工况下塔架的应力和位移,对三种工况下钢塔架的受力分析进行了比较,所得结论具有工程参考价值。 相似文献
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A novel design optimization model for placing frequencies of a wind turbine tower/nacelle/rotor structure in free yawing motion is developed and discussed. The main aim is to avoid large amplitudes caused by the yawing-induced vibrations in the case of horizontal-axis wind turbines or rotational motion of the blades about the tower axis in case of vertical-axis wind turbines. This can be a major cause of fatigue failure and might severely damage the whole tower/nacelle/rotor structure. The mathematical formulation considers a single pole tower configuration having thin-walled circular cross section with constant taper along the tower height. The nacelle/rotor combination is modeled as a rigid mass elastically supported at the top of the tower by the torsional spring of the yawing mechanism. Adequate scaling and non-dimensionalization of the various parameters and variables are given in order to make the model valid for a variety of wind turbine configurations and types of the material of construction. The resulting governing differential equation of motion is solved analytically by transforming it into a standard form of Bessel's equation, which leads to the necessary exact solutions for the frequencies and mode shapes. Several cases of study are examined for different values of the yawing stiffness and inertia parameters by considering both conditions of locked and unlocked yawing mechanism. Useful design charts are developed for placing the frequencies at their needed target values with no penalty of increasing the total structural weight of the system. In all, the developed model guarantees full separation of the system frequencies from the critical exciting yawing frequencies by proper choice of the optimization design parameters. 相似文献