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双叉式叶尖结构对风力机风轮振动的影响

Influence of double-fork blade tip structure on wind turbine vibration

  • 摘要: 为降低风力机风轮的振动,提出一种用于小型风力机的双叉式叶尖结构改型设计方案,通过风轮模态试验与风轮振动特性试验,测出改型设计前后风轮的模态参数、振动频率与振动加速度幅值,研究不同夹角的双叉式叶尖结构对风力机风轮振动特性的影响.通过对比未改型风轮与双叉式叶尖结构风轮的试验.结果发现:双叉式叶尖结构使风轮的二阶到四阶固有频率与阻尼比升高;双叉式叶尖结构可以调整风轮振动频率曲线的走势,使风轮更快地穿过共振区,且使共振点所对应的转速远离额定转速.在转速为360 r/min时风轮的振动加速度幅值产生突增,双叉式叶尖结构不会使突增消失,但可降低突增时的振动加速度幅值,且在风轮转速连续增大工况下,双叉式叶尖结构使风轮的振动加速度幅值降低.故双叉式叶尖结构能有效降低小型风力机风轮的振动,改良效果与叶尖夹角的关联性较大,相关结论为风轮减振研究提供一种新思路.

     

    Abstract: In order to reduce the vibration of the wind turbine wheel, a modified design scheme of double-fork blade tip structure for small wind turbine was proposed. Through the wind wheel modal test and wind wheel vibration characteristic test, the modal parameters, vibration frequency and vibration acceleration amplitude of the wind wheel before and after the modification design were measured to study the influence of the double-fork blade tip structure with different angles on the vibration characteristics of the wind turbine wheel. By comparing the test results of the unmodified wind wheel with double-fork blade tip structure wind wheel, it is found that the double-fork blade tip structure increases the second-order to fourth-order natural frequency and damping ratio of the wind wheel. The double-fork tip structure can adjust the trend of the wind wheel vibration frequency curve, make the wind wheel pass through the resonance zone faster, and make the speed corresponding to the resonance point far from the rated speed. When the rotation speed is 360 r/min, the vibration acceleration amplitude of the wind wheel increases suddenly. The double-fork blade tip structure will not eliminate the sudden increase, but it can reduce the amplitude of the vibration acceleration during the sudden increase. The double-fork blade tip structure reduces the vibration acceleration amplitude of the wind wheel under the condition that the rotation speed of the wind wheel is continuously increased. Therefore, the double-fork blade tip structure can effectively reduce the vibration of the wind wheel of small wind turbine, and the improvement effect has a greater correlation with the angle of the blade tip. The relevant research conclusions provide a new idea for the vibration reduction research of the wind wheel.

     

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