Abstract: There is an obvious "weng weng" noise when a refrigerator is running. After refrigerator noise and vibration spectrum was analyzed, it preliminarily judged that this abnormal noise was caused by resonance of discharge pipe which had a natural frequency around 50 Hz. The mechanism of discharge pipe resonance is analyzed in depth by using experimental modal analysis and modal simulation analysis, it was found that the middle part of discharge pipe had 50.8 Hz natural frequency mode. By adding software constraints to obvious modal part of discharge pipe, 50.8 Hz mode shape was limited. The refrigerator total noise reduced 2.6 dB(A) and single frequency noise about 20 dB(A). This "weng weng" abnormal noise almost disappeared when refrigerator was running.

Key words: Refrigerator noise, Piping system, Optimization design, Modal analysis