One of the significant vibration sources producing higher frequency noises in refrigerant compressors used for air conditioners or refrigerators is the reed valve which controls the refrigerant gas flow from the discharge port. In order to reveal the higher-frequency vibrations of the reed valve coupled with the compressed gas flow, we conduct a vibration test for an axisymmetrical simple model composed of the valve, the valve plate, the cylinder and the piston. First, compressed air is led into the flow chamber through a capillary tube at the piston center, and the valve is excited to induce a forced vibration in a frequency range from 50 to 500 Hz, Then, the fluid pressure in the flow chamber is measured for different cylinder volumes to determine the amplitude and the phase-lag relative to the valve vibration, thus resulting in a flow-induced vibration criterion for the reed valve. Secondly, a free vibration test of the reed valve is performed to verify that the reed valve actually induces a self-excited vibration when the vibration criterion obtained from the forced vibration test is satisfied. Finally, the fluid force determining the vibration frequency of the reed valve and the level of fluid excitation is examined.
