往复式制冷压缩机壳体振动声辐射特性的初步研究

A Study of the Vibration and Noise Radiation Characteristics of the Housing Shell of a Reciprocating Refrigeration Compressor

制冷压缩机是决定冰箱、冷柜等家电噪声水平的关键部件。本文首先分析往复式制冷压缩机噪声的类型以及传递途径,指出壳体是压缩机自身噪声向外辐射的最终载体;接着对某一压缩机的壳体进行了模态分析,以了解其固有振动特性;再在压缩机内部的四个支撑机芯的弹簧底部位置和排气管焊接处施加常值幅度的力谱,研究压缩机的受迫振动与声辐射。结果表明:对于此压缩机第1阶弹性变形模态为3kHz左右;四个支撑弹簧和排气管焊接处施加力激励,发现在1kHz以下,壳体的振动小且声辐射效率低,所以声辐射功率也小;随着频率增加,辐射效率提高,特别当超过第1阶变形模态之后辐射效率将大于1,并且此时由于结构模态的不断出现,振动能量和声辐射功率都维持在较大幅度范围内;不同激励点激励起各阶壳体模态振动的有效性不一样,排气管焊接点处比支撑弹簧处能更有效地激励壳体的振动与声辐射。

Compressor is the key component which determines the noise levels of refrigerators and freezers. In this paper, an analysis of the noise types and their transfer paths of reciprocating refrigeration compressors is carried out firstly; the housing shell is the ultimate carrier of noise radiation of compressors. A specific refrigeration compressor was selected as the research object. Modal analysis was performed using both the finite element method and modal test in order to know natural vibrations. A constant force spectrum was applied on the locations of support springs and the weld point of the housing and the discharge pipe respectively to study the dynamic response and noise radiation of the housing shell. The results show that the frequency of the first structural modal with elastic deformation is up to 3 kHz; with the applied force spectrum, vibration and sound radiation are rather weak under 1 kHz, and as the increase of frequency, the sound radiation efficiency ramps up. When the analysis frequency exceeds the natural frequency of the first structural modal with elastic deformation, intensive structural vibration occurs, and with the high radiation efficiency, the radiation sound power is appreciable. Due to the structural modal occurs intermittently when the frequency is above 3 kHz, the intensity of vibration and noise radiation maintains at noticeable levels. The location of the applied force shows different effects on the vibration excitation; the force on the weld point happens to be more efficient at exciting the housing shell＇s vibration than the force on locations of the supporting rings.