Theoretical Analysis of Noise and Vibration Generated by Gas Pressure Pulsation in Hermetic Compressors

Due to the intermittent nature of discharge flow in hermetic compressors, gas pulsation is a major source of noise, vibration and harshness (NVH) effects. In the presented study on gas pulsation noise of hermetic compressors, a model was developed where the thermodynamics aspects of the compression process and the vibro-acoustics aspects are coupled together. The vibro-acoustics submodel is based on finite element method, and it describes the two-way coupled interaction of compressor cavity acoustics and shell vibration. The thermodynamics submodel is based on compressor model developed in previous studies, PDSim. It is used to compute the discharge gas pulsations that excite the cavity. Meanwhile, the acoustics response in the cavity is coupled with the thermodynamics submodel though proper modeling of discharge valves. Simulations were conducted to validate the models developed in the current work as well as the to demonstrate how these modeling tools can help compressor manufacturers to gain better understanding of the physical reasons behind NVH effects of compressors. These tools can also provide guidelines on NVH oriented design optimization of compressors