大型风电机组偏航轴承动态性能研究

以大型风电机组偏航轴承为研究对象,在ANSYS平台上建立了偏航轴承的有限元模型,综合考虑轴向载荷和倾覆力矩的耦合作用,分析了滚动体与滚道的静态接触应力,并给出赫兹理论解。将静力学分析结果作为瞬态动力学分析的初始条件,对水平轴式风电机组偏航轴承的运转过程进行模拟仿真,得到了偏航轴承运转过程中滚动体的动态响应、应力变化及滚道的动态米塞斯应力变化情况。分析结果可为偏航轴承的动态设计及选型提供参考依据。     

风电偏航和变桨轴承的安装与维护

分析风电偏航和变桨轴承的特点,详细阐述了风电偏航和变桨轴承的安装方法和日常维护的关键要素。     

风电偏航轴承寿命计算与承载能力分析

在综合考虑球轴承以及回转支承基本设计理念的基础上,结合风机行业的GL设计规范与ISO标准等,基于风机偏航轴承坐标系下的真实载荷工况,合理运用相关的计算方法,准确梳理了偏航轴承寿命与承载能力计算的具体过程。结合实例对比了不同标准与规范的差异,结果表明,各种方法的计算结果虽有差异,但不影响对偏航轴承的基本判断,因此可以采用较为简单的算法对偏航轴承进行快速校核分析。     

基于可靠性理论的风电机组偏航轴承寿命预测

应用可靠性理论对大型风力发电机组偏航轴承进行寿命预测.以1.2MW级风力发电机组为例,依据风力发电机组的载荷谱,并且考虑到实际工作过程中机舱底板和塔架的变形对偏航轴承的影响以及偏航轴承摆动的工作状况,利用可靠性设计的方法计算了风力发电机组的可靠性寿命.在失效概率为10%的情况下,偏航轴承的运行时间为1.329×105小时,可靠度达到99.2%.     

风电偏航轴承接触力分布与疲劳寿命分析

根据风电偏航轴承的结构和受载特点,建立轴承的整体有限元模型并求解联合载荷下的接触力分布.为降低模型复杂性和减小计算规模,通过赫兹接触理论获取滚动钢球与滚道的接触力和变形关系;将这些变形特征赋予非线性的弹簧单元,使弹簧单元与钢球的接触变形特征一致,从而模拟钢球与滚道的接触,并通过经验公式和实验验证了模型的正确性.建立轴承...     

偏航、变桨轴承疲劳寿命的计算

计算了偏航、变桨轴承在轴向力、径向力和倾覆力矩共同作用下的最大钢球载荷,并根据Hertz接触理论计算了钢球组载荷分布的轴向和径向分量,将两者合成得到了钢球组的实际载荷分布,根据Lundberg-Palmgren理论,计算了内、外圈沟道的当量动载荷和额定动载荷,通过计算偏航、变桨轴承内、外圈的疲劳寿命得到整个轴承的疲劳寿命。     

局部结构改变对偏航轴承结构强度的影响

为了保证偏航轴承可靠运行,在其组件上置入了径向、轴向位移和温度传感器,以在线监测轴承的运行状态,并及时对其维护或更换。介绍了传感器在轴承组件中置入的位置,并分析了置入传感器后局部结构的改变对轴承结构强度的影响,分析表明:置入传感器后轴承沟道的最大接触应力增幅为10%～15%,且轴承的最大接触应力和结构变形对轴承上传感器置入槽的高度变化比较敏感,因此,在进行轴承结构设计时,应严格确定槽高,并在设计完成后重新校核轴承的承载能力。     

风力发电机偏航轴承载荷分布及接触角数值解法研究

基于赫兹弹性接触理论,推导了滚子与轴承内外圈接触变形时的接触刚度,建立了偏航轴承受复杂载荷时受力平衡的非线性方程组,井运用带有松弛因子的牛顿-拉夫逊法求解非线性方程组,得到了承载时偏航轴承各滚子的接触应力和接触角.最后,用经典理论公式和有限元方法对此方法计算结果进行了验证,证明了文中计算方法的正确性,为兆瓦级风力发电机轴承的设计计算提供了参考依据,具有一定的工程应用价值.     

风力发电机组偏航系统结构有限元分析

使用非线性有限元方法对风力发电机组偏航系统进行了结构分析。建立了风力发电机组偏航系统的有限元模型,提出了用gap单元模拟滚子,用多点约束模拟刹车器的简化方法。在极限载荷工况下对偏航系统关键部件的静强度进行了分析。分析结果显示了简化处理的合理性及优越性,表明在极限载荷下系统关键部件满足静强度要求。     

稳态偏航状态的风力机风轮气动力研究

根据水平轴风力机的特征参数建立了偏航致动盘的涡流柱面模型,用稳态偏航状态下的叶素动量理论计算出周向诱导流动因数。以Pitt-Peters模型为收敛条件,考虑了风轮的偏航角参数,建立计算水平轴风力机轴向诱导流动因数的计算模型,并用C++语言在VC环境下进行仿真计算,解决了气动设计和性能计算的关键问题,并通过实例验证了仿真过程的可行性。     

High-pressure behavior and tribological properties of wind turbine gear oil

Different types of synthetic polyalphaolefin (PAO) oils and a mineral oil are considered in this study. High-pressure viscosity test was done and pressure-viscosity coefficient was measured for all sample oils. Results showed the better performance of PAO oils than the mineral oil. Authors also tested some other tribological properties such as low-temperature behavior, bulk property, frictional coefficient, and wear behavior, which are important for wind turbine gear oil. Low-temperature behavior and frictional property of PAO oils exhibited the better results. Study also showed that the prediction of low-temperature fluidity is possible using the sound velocity in the oil. Finally, the presence of polymethakrylate (PMA) absorbent in PAO oil exposed comparatively better results among all PAO oils.     

Design of elastomeric bearing system and analysis of it mechanical properties

This paper proposes a new type of bearing system. In this study, a method for design of on elastomeric bearing system and its mechanical property analysis are carried. Experimental and theoretical studies of the elastomeric bearings with fiber reinforcement were proved effective new lightweight bearing system. The fibers in the bearings for isolation are assumed to be flexible in extension, in contrast to the steel plates in the conventional bearing system. Several kinds of bearing systems in the form of long strips are designed, fabricated and tested. The results suggest that it is possible to produce the economical and effective fiber-reinforced elastomeric bearing that matches the behavior of a steel-reinforced bearing. Feasibility and advantages of the proposed bearings are illustrated by the application of the analytic procedure to the structure system. Results obtained here are reported to be an efficient approach with respect to bearing system and design of bearing against shock absorbing system when compared with other conventional one.     

Influence of bearing stiffness on the static properties of a planetary gear system with manufacturing errors

Hybrid finite element analysis was used to analyze the influence of bearing stiffness on the static properties of a planetary gear system with manufacturing errors. The effects of changes in stiffness were similar for most of the manufacturing errors. State variables were most affected by the stiffness of the planet bearings. Floating either the sun or carrier helps to equal load sharing and minimizes the critical tooth stress. The effects of a floating sun and carrier are similar, but it is not recommended that both float, because this can induce greater critical tooth stress. Planet bearing stiffness should be optimized. Both load sharing and critical tooth stress should be considered to determine optimal bearing stiffness.     

Pressure viscosity coefficients and traction properties of synthetic lubricants for wind turbine gear systems

Synthetic lubricants are increasingly used to provide equipment reliability for wind turbine gear boxes. The majority of synthetic lubricants used today are based on polyalphaolefins. In gear systems where contact pressures are high, the pressure viscosity coefficient and traction values of the lubricant are important fundamental properties. A comparison of these properties for a wind turbine lubricant based on a polyalphaolefin and two lubricants based on polyalkylene glycols has been undertaken. Pressure viscosity coefficients were calculated from viscosity measurements made using an ultra‐high pressure falling needle viscometer at pressures up to 50 000 psi. Significant differences in properties were observed with both polyalkylene glycol lubricants showing lower pressure viscosity coefficients and much lower traction values. A calculation of the film thickness values in the Hertzian contact zone suggests that polyalkylene glycol lubricants may provide elastohydrodynamic films that are approximately 25% thicker than polyalphaolefin lubricants. Copyright © 2012 John Wiley & Sons, Ltd.     

风力发电机齿轮箱测试内齿圈异响分析

对齿轮箱做振动测试和分析,找到齿轮箱异响呈现的特性,为齿轮箱故障诊断提供依据。     

基于混合编程的风力发电机组轴承故障诊断系统

为了保障风力发电机组的安全可靠运行,结合风力发电机组中轴承故障特性,研发了一套针对风力发电机组轴承的故障诊断软件。该软件利用Visual C++和Matlab混合编程实现,可以对风机轴承进行数据采集和故障诊断。根据诊断结果可以对机组工作状态做出判断,针对异常情况可以帮助工作人员查明故障原因,提前做好预警和维护计划,提高风力发电效益。最后在模拟实验台上采集了故障轴承的振动信号并用该软件进行了时频分析、解调分析和倒谱分析,分析结果与实际故障吻合良好。