尾缘锯齿齿角变化对空调外机轴流风叶声场影响的试验研究

为探索尾缘锯齿齿角变化对空调外机轴流风叶声场的影响，根据《声学声压法测定噪声源声功率和生能量级反射面上方近似自由场的工程法》(GB/T 3767—2016)规定的声压级测量方法，在额定转速下采用传声器阵列对不同角度的尾缘齿角风叶进行时间平均声压级测量，利用波束形成技术探究风叶噪声源分布规律。试验结果表明：随着尾缘齿角的增加时间平均声压级均值非线性减小，尾缘齿角为90°的风叶比尾缘齿角为0°的风叶时间平均声压级均值降低了3.2～5.8 dB;随着声辐射频段的增加声源位置向叶尖方向移动且声源的声压级逐渐降低，同时锯齿齿角越大，声源位置随频率增加移动速度越快，移动距离越大。低频段声源位置随齿角变化较小，高频段声源位置随齿角变化较大。为低速小展弦比轴流风叶的降噪工作提供试验参考。

Experimental Study on the Influence of Trailing Edge Serrated Tooth Angle on the Sound field of Air Conditioner External Axial Flow Blade

To explore the influence of trailing edge serrated tooth Angle changes of air conditioner axial flow blades on the sound field. The time average sound pressure level measurement of trailing edge tooth Angle blades with different angles was carried out by a microphone array according to the corresponding national standard at rated speed. And the distribution law of blade noise source was investigated by beamforming technology. The test results show that the mean time-averaged sound pressure level decreases nonlinearly with the increase of trailing edge tooth angle. Meanwhile, compared with the blade with a trailing edge tooth Angle of 90°, the mean time-averaged sound pressure level of a blade with a trailing edge tooth Angle of 0° decreases by 3.2~5.8dB. The position of the sound source move to the tip direction, and the sound pressure level of the sound source decreases gradually with the increase of the acoustic radiation frequency band while the more significant the trailing edge serrated tooth Angle. The source location with the frequency increases the faster the movement, the greater the movement distance. The sound source location varies less with tooth angle in the low-frequency band and more with tooth angle in the high-frequency band. Accordingly, it provides an experimental reference for the noise reduction of low-speed small spreading chord ratio axial flow airfoil.