Development of Gas Pulsation Damping Device for Twin Screw Refrigeration Compressor

For the purpose of improving discharge gas pulsation characteristic of twin screw refrigeration compressor, a gas pulsation damping device following the principle of Helmholtz resonator was developed. In consideration of the oil-gas two-phase flow in the compressor discharge chamber, a two-phase sound speed calculation model was established. Then the resonant frequency of damping device can be evaluated. The gas pulsation damping device applied to twin screw refrigeration compressor was developed. Experimental investigation was carried out to analyze the effects of discharge temperature and lubrication oil flow rate on the performance of damping device. And the vibration characteristic of compressor with the damping device was compared with the one without damping device. It is concluded that there exists an optimal sound speed of R134a to achieve the maximum damping ratio when the lubrication oil flow rate keeps constant. With the increasing oil flow rate, the optimal value of R134a sound speed increases. There also exists an optimal sound speed of the two-phase fluid, and optimal value keeps constant but the damping ratio increases as the oil flow rate increases. The vibration acceleration of compressor under-chassis under first-order gas pulsation frequency can be reduced by 36.2% to 40.9% as the compressor is equipped with the damping device.