依据现有的叶片尾迹宽度计算公式,计算了一空调室外机风机叶片的尾迹宽度,然后,以此尾迹宽度为参考基准,设计了两组不同形状和大小的锯齿形叶片尾缘,制作并试验研究了锯齿形尾缘对风机气动噪声的影响规律。结果表明,锯齿尾缘有明显降噪效果,正弦形锯齿较正三角形更好。锯齿尾缘通过降低宽频噪声降噪,而对离散噪声影响很小。采用与叶片尾迹宽度相近的尾缘锯齿尺寸,气动噪声降低效果最为显著。
The blade wake width of axial fan in an outdoor air conditioner is calculated based on the formula proposed by Fukano.According to the calculated wake width,two kinds of serrated trailing edges with different shape and size were designed.The influence of the two serrated trailing edges on aeroacoustic noise of the air conditioner was experimentally studied in an anechoic chamber. The result shows that the two serrated trailing edge both reduces the noise level,but the sinusoid serrated trailing edge has stronger ability in noise reduction than the triangular.The serrated trailing edge works mainly in broadband noise region,but on the rotating discrete noise nearly has no influence.When the trailing edge size is close to wake width,it may be optimum for noise reduction.The study provides a further guideline in using serrated trailing edge for fan noise reduction.