空调室外机低频噪声源识别及优化

Air conditioner outdoor unit low frequency noise identification and optimization

某空调运行时室外机存在明显低频噪声,对应峰值为192 Hz。对噪声源进行定位,按照实际运行载荷单开压缩机和风机系统体验噪声,单开风机系统时不存在低频噪声,单开压缩机时“嗡嗡”声极其微弱,说明低频噪声不是由风机系统或者压缩机系统直接引起。按压侧板中部异常噪声消失,说明“嗡嗡”声由侧板直接发出,测试侧板速度,发现侧板192 Hz振动偏大。通过传递路径和模态分析对侧板振动异常原因进行分析,模态仿真和测试显示侧板和排气管固频与压缩机四倍谐波192 Hz接近,引起了侧板振动偏大。通过管夹优化排气管固频,避开192 Hz,并将压缩机减振胶垫由53 HA硬度更换为43HA硬度,增加胶垫减振效果,低频噪声基本消失。

When an air conditioner is running,there is an obvious low-frequency noise in the outdoor unit,and the corresponding peak value is 192 Hz.Locate the noise source,according to the actual operating load,the compressor and fan system are only turned on to experience the noise.There is no low-frequency noise when the fan system is only turned on,and the low-frequency noise is extremely weak when the compressor is only turned on,indicating low-frequency noise is not directly caused by the fan system or the compressor system.Press the middle of the side panel with fingers and the abnormal noise disappears,indicating that the low-frequency noise was directly emitted by the side panel.After testing the acceleration of the side panel,it was found that the 192 Hz vibration of the side panel was too large.The cause of abnormal vibration of the side plate is analyzed through the transfer path and modal analysis.The modal simulation and test show that the frequency of the side plate and the exhaust pipe is close to the quadruple harmonic vibration of the compressor at 192 Hz,which causes the side plate to vibrate too large.In order to keep the fixed frequency of the exhaust pipe away from 192 Hz,a pipe clamp was added to the exhaust pipe.In order to increase the vibration damping effect of the rubber pad,the compressor vibration damping rubber pad was changed from 53 HA hardness to 43 HA hardness.Through these two measures,the low-frequency noise basically disappeared.