Two-dimensional Acoustic Analysis by Concentrated Mass Model

Abstract

The purpose of this study is to model the acoustic field in which gas and liquid coexist in a separated state, as typified by the space under the motor of a compressor installed in an air conditioner, as a concentrated-model consisting of masses, connecting springs, and connecting damping, and to propose a sound field design that reduces noise through analysis using this model. In order to validate the modeling of a sound field where gas and liquid coexist, eigenvalue analysis is performed using the mass and stiffness matrices of the model, and the effectiveness of the model is confirmed by comparing the obtained eigen-frequencies and eigen-modes with the theoretical solution. From the results of the forced vibration analysis using the concentrated-model, it was confirmed that the sound pressure peak becomes very large when the resonance occurs in the liquid region in the acoustic field, and the acoustic field design using the gas space as a dynamic vibration absorber was proposed as a method to suppress the sound pressure peak. The effect of this method was verified through analysis.