S型叶尖对风力机气动噪声的影响研究

Study on aerodynamic noise of wind turbine with Ogee type tip shape

运用延迟分离涡模拟（DDES）对传统直叶尖风轮和S型叶尖风轮尾迹流场声场进行研究,重点对风轮输出功率、叶尖区域声辐射进行了分析。结果表明：S型叶尖风轮输出功率提高;所选观测点上S型叶尖风轮总声压级为96.12 d B,比传统直叶尖风轮减少2 d B;S型叶尖频谱图中声压级总体处于20-40 d B,比传统直叶尖低10 d B左右,声压级降低效果比较明显;风轮辐射声总声压级随着测点距离远离风轮逐渐衰减,S型叶尖风轮的总声压级比传统叶尖风轮低,降幅在1-8 d B;相对于传统直叶尖风轮,S型叶尖风轮在4条所选观测线上总声压级降低幅度分别增大了22.0%,24.6%,29.6%,46.0%。沿着半径增大方向,S型叶尖的总声压级的降低幅度要大于传统直叶尖,辐射声降低效果明显。DES方法对于风力机流场声场的模拟计算是可行的。

The wake flow field and sound field of rotor between the Ogee type tip and traditional tip were studied via the Delayed Detached Eddy simulation （DDES）. The wind power output and the acoustic radiation tip area of wake and sound field were analyzed in detail. The results showed that the turbine output power of the Ogee type tip was increased in compared with the traditional tip. While, the total sound pressure level of the tip with the Ogee type was 96.12 dB, which was declined 2 dB compared with the total sound pressure level of traditional tip on the local observed position. Meanwhile, the sound pressure level was reduced dramatically around 10 dB which contained 20-40 dB in the spectrum. The total sound pressure level of rotor was decreased gradually with the axial displacement of wind turbine. The tendency line of the total sound pressure level of the Ogee type tip was also lower than that of the traditional tip, and the decreasing amplitude was around 1-8 dB. Compared with traditional tip, the decreasing amplitude on four tendency lines of the total sound pressure level of the Ogee type tip were increased 22.0%, 24.6%, 29.6%, 46.0%, respectively. The decreasing amplitude of the total sound pressure level of the ogee type tip was larger than the traditional tip along with the direction of radial displacement, while the effect on noise was declined obviously. Hence, it is available to study the flow field of sound field of wind turbine by the DES simulation method.