Abstract: When the refrigerator compressor runs at high speed, the refrigerant pulsation causes low-frequency noise in the return pipe. The refrigerant pulsation, which transmit to the refrigerator through the pipe, will also cause low-frequency noise. The sound wavelength of low-frequency noise has strong penetration ability and wide influence range, which is easy to cause subjective annoyance to users. To solve this problem, firstly, the acoustic vibration coherence method was used to identify the low-frequency noise, and the main noise frequency band is 450 Hz~700 Hz. Then, the acoustic simulation and CFD simulation methods are used to design and optimize the muffler structure by controlling the regenerative noise, and the optimal muffler structure is obtained. The experimental results show that the muffler is effective, the noise fluctuation decreases by 1.6 dB and the average noise value decreases by 1.5 dB.

Key words: Refrigerant pulsation, Low-frequency noise, CFD simulation, Muffler