空调室外机低频声改善

The optimization of low frequency noise of outdoor unit of air conditioner

针对某变频空调室外机在压机转频95Hz以上发出令人烦恼的2倍频低频"哄哄"声,实测了压机以及配管系统的频响曲线,并采用有限元方法计算压机及配管系统的固有频率,试验与仿真结果一致,仿真结果表明配管系统在193Hz处存在共振,分析此模态的应变能,确认支撑架为刚度薄弱环节。为了避开了压机运行产生低频声的频率范围,通过改善支撑架的焊接方式提高了的配管系统固有频率。试验结果表明,2倍频的低频"哄哄"声降低20d B以上,低频声能量降低23%以上,有效的消除了室外机运转时的低频"哄哄"声。

The annoying low frequency noise was radiated by inverter air conditioner outdoor unit when compressor was running above 95 Hz, the frequency of annoying noise was twice of compressor's running frequency. In order to look for the reasons of low-frequency noise, the frequency response curves of compressor and piping system were tested and modal simulations of compressor and piping system were carried out by finite element method, simulation results were consistent with testing results. Simulation results showed that Piping system's resonance frequency was 193 Hz that was according to frequency of low-frequency noise, then the modal strain energy was analyzed, and the supporting frame was confirmed to be the weakest stiffness structure. Piping system's resonance frequency was increased by optimizing welding style of supporting frame, the resonance frequency and low-frequency noise frequency was avoided. The test result showed that the sound pressure level of low-frequency noise had been reduced over 20 d B, the energy of it had been decreased over 23%. Finally, the low-frequency noise of outdoor unit was eliminated effectively.