水平轴风力机偏航与俯仰尾流特性

Yaw and tilt wake characteristics of horizontal axis wind turbine

  • 摘要: 风力机的尾流干扰效应是影响风场下游风力机性能和风场出力的主要因素,通过调整风轮姿态可有效改善尾流干扰效应,但同时也引入了更为复杂的非定常气动特性和尾流场分布。为了研究风轮姿态控制的尾流特性,基于升力线和自由涡尾迹模型建立了水平轴风力机气动和尾流仿真模型,以NREL 5MW风力机为研究对象,在额定风速条件下,研究了叶轮偏航和俯仰工况下的尾流结构特性。在此基础上,对存在风切变和塔架影响时的风力机偏航和俯仰工况产生的尾流干扰进行了分析。研究结果表明:风轮的偏航和俯仰会引起尾流涡结构失稳提前、远尾流区湍流度增大,同时会导致尾流中心发生偏转和尾流作用区域减小,并加快速度亏损恢复,降低尾流效应对下游的干扰。风切变会产生类似风力机俯仰的效果,使得尾流抬升,作用区域减小。塔架对近尾流区的干扰较为显著,而俯仰控制会降低塔架对尾流的干扰。

     

    Abstract: The wake interference of wind turbines is the main factor affecting the performance and output of wind turbines downstream of the wind farm. By adjusting the attitude of the wind turbine, the wake interference effect can be effectively improved, but it also introduces more complex unsteady aerodynamic characteristics and wake field distribution. In order to study the wake characteristics of wind turbine attitude control, based on the lifting-line and free vortex wake model, the aerodynamic wake model of the horizontal axis wind turbine is established. Taking the NREL 5MW wind turbine as the research object, under the condition of rated wind speed, the wake characteristic of the turbine under yaw and tilt conditions is studied. The wake disturbance of the wind turbine yaw and tilt condition under the influence of wind shear and tower is further analyzed. The results show that, yaw and tilt will cause the instability of the wake vortex structure in advance, the turbulence intensity in the far wake region will increase, the wake center will deflect and the wake action area will decrease. In addition, yaw and tilt will accelerate the recovery of velocity deficit and reduce the interference of wake effect on the downstream. Wind shear will exert a similar effect on the tilt of the wind turbine, which will raise the wake and reduce the area of wake. The interference of the tower to the near wake region is more significant, and the tilt control will reduce the interference of the tower to the wake.

     

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