Noise control of a twin-screw refrigeration compressor

Twin-screw compressors are widely used in refrigeration systems, but noise is a serious problem during operation. Gas pulsation is the main noise excitation source in twin-screw compressors, and the noise has significant fundamental harmonic characteristics. In this study, the noise characteristics of a screw compressor were experimentally investigated, which provides insight into the noise control technology of the compressor. The analysis incorporated the noise control theory and the structural characteristics of the experimental compressor. The noise reduction schemes including half-wavelength tube, Helmholtz resonator, and multi-cavity series muffler were proposed, and the noise attenuation performances of these methods were studied experimentally. The results showed that application of these noise reduction strategies significantly reduced the noise level by 10.7 dBA, 10.9 dBA, 7.2 dBA, and 10.2 dBA at the male rotor side, the female rotor side, the suction side, and the exhaust side, respectively. Comparative test results indicated that the use of the exhaust muffler and the attenuation scheme on the exhaust bearing block was most effective and it reduced the compressor noise level by 8.17 dBA. These results provided useful guidance for designing a quiet compressor.