Acoustic Emissions from Wind Turbine Blades

ABSTRACT Research on broadband aerodynamic noise from wind turbine blades is becoming important in several countries. In this work, computer simulation of acoustic emissions from wind turbine blades are predicted using quasi empirical model for a three-bladed horizontal axis 3 MW turbine with blade length ~47 m. Sound power levels are investigated for source and receiver height of 80 m and 2 m above ground and located at a distance equal to total turbine height. The results are validated using existing experimental data for Siemens SWT-2.3 MW turbine having blade length of 47 m, as well as with 2.5 MW turbine. Aerofoil self-noise mechanisms are discussed in present work and results are demonstrated for wind speed of 8 m/s. Overall sound power levels for 3 MW turbine showed good agreements with the existing experiment data obtained for SWT-2.3 MW turbine. Noise map of single source sound power level, dBA of an isolated blade segment located at 75 %R for single blade is illustrated for wind speed of 8 m/s. The results demonstrated that most of the noise production occurred from outboard section of blade and for blade azimuth positions between 80° and 170°.

摘要：针对风力机叶片宽带气动噪声的研究在多个国家愈发受到重视。本研究针对叶片长度约47米的三叶水平轴3兆瓦（MW）风力发电机组，采用准经验模型对其叶片的声学辐射开展计算机仿真预测。针对声源高度为地面以上80米、接收点高度为地面以上2米，且接收点与机组的距离等于机组总高度的场景，本研究探究了其声功率级特性。研究采用叶片长度为47米的西门子（Siemens）SWT-2.3兆瓦风力发电机组，以及2.5兆瓦风力发电机组的现有实验数据对仿真结果进行了验证。本研究探讨了翼型（Aerofoil）自噪声的产生机理，并给出了风速为8米/秒时的仿真结果。3兆瓦风力发电机组的总声功率级与SWT-2.3兆瓦风力发电机组的现有实验数据吻合良好。本研究给出了风速为8米/秒时，单叶片75%叶展位置处独立叶片段的单源A计权声功率级（dBA）噪声云图。结果表明，大部分噪声产生于叶片的外侧区域，且对应叶片方位角介于80°至170°之间。