风力发电设施的低频噪声分析与降噪措施研究

In recent years, wind power industry developes rapidly in our country. The noise pollution of wind generator appears gradually. Residents near the wind farm are complaining about the noise of the wind turbines. And even birds also significantly reduced nearby wind farms. The noise problem even affected the development of wind power industry. Therefore, in order to reduce noise pollution and make the wind power industry grow steadily. Researching the wind noise problem is urgent. And the measurement results from wind farm show that the noise is in accordance with all relevant national noise standard. The components of wind noise is mainly the low-frequency-noise. The impact of low frequency noise on hearing is not big. But it will cause discomfort of the other senses of human being. The current noise standard is used A weighting network sound level. It only reflects the influence of comprehensive sense degrees by ear with different frequences. And the high and low frequency bands are greatly attenuated. So the wind noise should not be properly evaluated using A sound level. By using the ways of numerical simulation and measurement, this program will analyze the source of the lower frequency noise from wind turbines. The relationship between the internal structure of the wind power unit and mechanical noise will be calculated. And the relations between wind power blade aerodynamic noise and parameter of the blades, wind force and wind direction and terrain are also analyzed. Then, the approaches to reduce the mechanical noise and aerodynamic noise are studied. And the structure of wind power equipment are optimized, to effectively reduce the low-frequency noise of wind farms. Finally, the noise testing standard and measuring method of low-frequency noise will be given.

近年来我国风电产业发展迅速，风电机组的噪声污染逐步显现，尽管现场测量噪声并未超过国家的相关噪声标准范围，但居民对风电噪声的投诉越来越多，风电场附近鸟类也明显减少，噪声问题甚至影响了风电产业发展。为此，迫切需要研究风电噪声，减少噪声污染，使风电产业健康持续发展。 经分析，风电噪声主要为低频成份，低频噪声对人的听觉影响不大，却引起其它感官的不适。而现行噪声标准所采用的A计权网络声级，反映了人耳对不同频率噪声的综合感觉程度，它对低频段进行了大幅衰减，故风电噪声不应采用A声级来评价。 本项目先研究不同频段噪声对人的影响，再通过数值模拟和现场测量，分析风电机组的低频噪声源；研究风电机组内部结构与机械噪声之间的联系；揭示风力发电叶片的气动噪声与叶片、风力及地形的关系；分析降低机械噪声和气动噪声的途径；对风力发电装备进行结构优化，有效降低风电场的低频噪声，并提出针对风机低频噪声的环境检测标准和测量方法。

近年来我国风电产业发展迅速，风电机组的噪声污染逐步显现，尽管现场测量噪声并未超过国家的相关噪声标准范围，但居民对风电噪声的投诉越来越多，风电场附近鸟类也明显减少，噪声问题甚至影响了风电产业发展。为此，迫切需要研究风电噪声，减少噪声污染，保持风电产业健康持续发展。. 经分析，风电噪声主要为低频成份，低频噪声对人的听觉影响不大，却引起其它感官的不适。而现行噪声标准所采用的A计权网络声级，反映了人耳对不同频率噪声的综合感觉程度，它对低频段进行了大幅衰减，故风电噪声不应采用A声级来评价。. 通过研究认为：1）利用流体分析软件FLUNT精确模拟1.5MW风力机流场，表明设计风力机叶片在额定工况下已基本达到设计功率要求，叶片周围也没出现大面积失速现象。2）通过模拟对称机翼NACA0018的涡流噪声，分析机翼周围静压、动压、流速、涡流和声场特点，验证了采用LES和声类比相结合的方法计算翼型涡流噪声可靠性。3）在截面相对来流的攻角不是很大的情况下，风力机叶片气动噪声的主要声源部位分布在叶片尾缘和尾流中。4）沿叶片径向，声压级迅速增大，相对来流的大小对于气动噪声的影响比攻角小幅度变化要明显。相对来流的大小很大程度上取决于叶片旋转速度。5）声能量主要集中在低频，降低风力机叶片气动噪声的一个主要方向是降低其低频噪声。6）通过分析实测的风力机噪声信号，表明传统的A计权将人为损耗低频信息，仅凭A计权后的声压级作为评价风力机噪声的唯一指标是不合理的。. 发表期刊论文11篇、会议论文4篇。其中EI收录4篇、ISTP收录2篇。获发明专利6项。培养硕士研究生3人。通过本项目研究，分析风电机组引起的低频噪声对人产生不适的影响关系，掌握风电机组机械噪声和气动噪声的特性，分析风电机组机械噪声和气动噪声的影响因素，揭示风电机组噪声强度与其影响因素之间的内在联系与规律，提出减少噪声影响的有效方法与措施。