大型风力机叶片载荷智能控制系统应用与机理研究

发布时间：2018-06-18 17:10

本文选题：海上风电 + 柔性尾缘襟翼　；参考：《中国科学院研究生院(工程热物理研究所)》2015年硕士论文

【摘要】：由于海上风电具有风速高、不占地、沙尘少、运行稳定以及适合大规模开发等优势,全球风场建设已呈现出从陆地向海上发展的趋势。为了降低单位度电成本,海上风电叶片的尺寸越来越大,目前已并网发电的V164-8.0 MW风力机其叶轮直径已高达160 m左右。叶片尺寸变大后,其柔性增强,叶轮平面内风速差异变大,这都会削弱气弹稳定性,增大叶片载荷,从而容易导致叶片损坏。对于海上风电来说,其制造成本和运维成本都非常庞大,因此对风力机的可靠性提出了更高的要求,而提高可靠性的关键在于降低叶片疲劳载荷和极限载荷。目前,风力机的降载主要靠变桨来实现,但这种技术动作缓慢已无法应对大型叶片上的局部随机波动载荷。为了发展更加有效的降载方法,早前诞生于直升机领域的“智能叶片”概念最近已被研究人员成功地引入到风力机领域。它是一种主动型的流动控制技术,通过传感器,控制器和作动器的组合装置来实现局部气动表面变形。其原理是通过局部翼型表面变形后升力的变化来调节叶片受载。在众多“智能叶片”作动装置中,柔性尾缘襟翼(DTEF)由于其具有反应快速,调节范围广,流动扰动小等优点,从而被公认为最有商业应用价值的作动装置。针对这一领域,本课题组已成功搭建了基于DTEF的整机仿真平台,并讨论了其对于标准湍流风况下疲劳载荷以及风速极端变化下极限载荷的控制效果。在课题组前期工作的基础上,为推动柔性尾缘襟翼(DTEF)进一步的工业应用,本文进一步开展了以下工作：(1)首先,本文集中探讨了DTEF的四组主要参数：中心位置Rf/R,展长Lf/L,占弦比Cf/C以及最大摆动角度|φf,max|对控制效果的影响。结果发现：大体上,其控制效果是随着这四组参数的增大而增大的。但例外的是,叶尖处DTEF的控制效果在额定风速前后差别迥异。(2)接着,本文选取了一组典型的DTEF参数,分析了DTEF控制系统在伴随风向变化的相干阵风模型ECD风况下的作用,该风况代表了一种风速风向均发生急剧变化的风况,是IEC标准中规定在发电状况下需要进行载荷校核的风模型。结果表明：DTEF控制系统能够有效地降低ECD风况下载荷的波动,具体地,其叶根挥舞方向弯矩和叶尖变形量的波动幅度均减少了30%左右。(3)最后,本文探讨了三种工程上可实现的传感器信号方案,其分别为：加速度、叶根挥舞方向弯矩和叶尖变形量。并分析,比较了三种方案之间DTEF控制效果的差异。结果表明叶根挥舞方向弯矩信号最优,其次为加速度信号,叶尖变形量效果最差。(4)此外,本文也从叶片流动-结构间的气弹耦合机理出发,分析了DTEF控制系统背后的流动控制机理。经研究发现：DTEF与叶片周围气动力反相运动,从而打乱了叶片周围气动力与当地加速度之间较好的同步性,增加了叶片流动-结构系统间的阻尼,因此该控制系统能有效地抑制叶轮与传动链其他部件载荷的波动。
[Abstract]:Due to the advantages of high wind speed, no land occupation, less sand dust, less dust, stable operation and suitable for large-scale development, the global wind field has been developing from land to sea. In order to reduce the unit cost of electricity, the size of the blade of the offshore wind power is getting bigger and bigger, and the diameter of the impeller diameter of V164-8.0 MW wind turbine, which has been connected to the grid before the mesh, is the diameter of the wind turbine. It has reached about 160 m. When the blade size becomes larger, its flexibility increases and the difference of wind speed in the plane of the impeller becomes larger. This will weaken the stability of the aeroelastic, increase the load of the blade, and lead to the damage of the blade. For the sea wind power, the cost of manufacturing and the operation and maintenance cost are very large, so the reliability of the wind turbine is higher. The key to improve the reliability is to reduce the blade fatigue load and the ultimate load. At present, the load reduction of the wind turbine is mainly realized by the variable propeller, but this technique is slow to cope with the local random fluctuating load on the large blade. In order to develop a more effective load reduction method, the "intelligent blade" was born earlier in the helicopter field. The concept has recently been successfully introduced into the field of wind turbines by researchers. It is an active flow control technology that uses a combination of sensors, controllers and actuators to achieve partial aerodynamic surface deformation. The principle is to regulate the loading of the blade through the change of the lift force after the surface deformation of the local airfoil. With the advantages of rapid reaction, wide adjustment range and small flow disturbance, the flexible tail flaps (DTEF) have been recognized as the most commercial actuating devices. In this field, our group has successfully built a DTEF based simulation platform, and discussed its fatigue in the standard turbulence wind condition. In order to promote the further industrial application of flexible tail flaps (DTEF), the following work has been carried out in this paper on the basis of the earlier work of the project group. (1) first, this paper focuses on the four main parameters of the four groups: the center position Rf/R, the extended Lf/L, and the chord ratio Cf/C As well as the effect of the maximum swing angle F and max| on the control effect, it is found that, in general, the control effect increases with the increase of these four sets of parameters. But the exception is that the control effect of DTEF at the tip of the blade is very different before and after the rated wind speed. (2) then a group of typical DTEF parameters are selected and the DTEF control system is analyzed. The wind condition, which is accompanied by wind direction change in the coherent gust model ECD wind condition, represents a sharp change in wind speed and wind direction. It is a wind model required to check the load in the IEC standard. The result shows that the DTEF control system can effectively reduce the fluctuation of the download load of the ECD wind condition, specifically, The wave amplitude of the blade root waving bending moment and leaf tip deformation decreased by about 30%. (3) finally, this paper discussed the sensor signal scheme which can be realized in three kinds of engineering, which are the acceleration, the direction bending moment of the leaf root and the deformation of the tip of the leaf. The difference between the effect of the DTEF control between the three schemes is compared. The results show that the difference between the control effect of the three schemes is compared. The blade root waving bending moment signal is the best, followed by the acceleration signal, the blade tip deformation effect is the worst. (4) in addition, this paper also analyzes the flow control mechanism behind the DTEF control system based on the aeroelastic coupling mechanism between the blade flow and the structure. It is found that the reverse movement of DTEF and the aerodynamic forces around the blade has disrupted the blade cycle. The good synchronization between the aerodynamic force and the local acceleration increases the damping between the blade flow and the structure system, so the control system can effectively restrain the fluctuation of the load of the impeller and other parts of the drive chain.
【学位授予单位】：中国科学院研究生院(工程热物理研究所)
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TM315

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