制冷压缩机振动噪声控制技术

Control technologies of vibration and noise in refrigeration compressor

双螺杆式制冷压缩机和离心式制冷压缩机广泛应用于制冷空调系统中,但其振动噪声问题不容忽视。本文分别介绍双螺杆式制冷压缩机和离心式制冷压缩机振动噪声的产生原因,阐述制冷压缩机振动噪声的控制手段,并介绍减振降噪技术在制冷压缩机中的实际应用案例。研究表明:双螺杆式制冷压缩机排气气流脉动诱发的噪声显著。以宽频穿孔管消声器降噪技术为例,变频双螺杆式制冷压缩机排气腔内采用宽频穿孔管消声器后,在2 400~4 200 r/min转速区间内气流脉动和噪声声压级均有改善,其中在3 600 r/min和4 200 r/min转速时气流脉动幅值均衰减60%以上,噪声声压级分别降低6.8 dB(A)和3.0 dB(A)。制冷系统的排气管道应用宽频穿孔管消声器后,前4阶气流脉动幅值衰减75%以上,其噪声声压级降低8 dB(A)以上。离心式制冷压缩机叶轮参数是影响气动噪声的关键因素之一,以优化叶片尾缘斜掠角为例,叶片尾缘斜掠角为15°时相较叶片尾缘无斜掠角,压缩机噪声声压级降低4.3 dB(A)。

Twin screw refrigeration compressors and centrifugal refrigeration compressors are widely used in refrigeration and air-conditioning systems. However, the vibration and noise problem can not be ignored. The generation of vibration and noise of twin screw refrigeration compressors and centrifugal refrigeration compressors are introduced, the control methods of vibration and noise are discussed, and the application cases of vibration reduction and noise control technologies are introduced. The researches show that the noise induced by the discharge pulsation of the twin screw refrigeration compressor is dominant. Taking the wide frequency noise control technology of perforated tube muffler as an example, when a wide frequency perforated tube muffler is applied to the discharge housing of the variable frequency twin screw refrigeration compressor, the gas pulsation and noise sound pressure level between 2 400 r/min and 4 200 r/min are both improved. In particular, the amplitudes of gas pulsation at 3 600 r/min and 4 200 r/min are both attenuated by more than 60%, and the sound pressure levels are reduced by 6.8 dB(A) and 3.0 dB(A), respectively. When the wide frequency perforated tube muffler is applied to the discharge pipe of the refrigeration system, the amplitudes of the first four orders gas pulsation are attenuated by more than 75%, and the noise sound pressure levels are reduced by more than 8 dB(A). The impeller parameters of centrifugal refrigeration compressor are one of the key factors affecting aerodynamic noise. Taking the optimization of the blade trailing edge sweep angle as an example, the sound pressure level of compressor noise with the blade trailing edge sweep angle of 15° is 4.3 dB(A) lower than that without sweep angle.