Investigation of the refrigerator bottom cabinet cavity acoustic behavior

Abstract

This thesis investigates the computational and experimental analysis for the acoustic behavior of a bottom cabinet cavity in a refrigerator. The finite element and analytical approaches are used in order to determine the natural frequencies and associated mode shapes of the bottom cabinet cavity. The sound of bottom cabinet cavity is related to its frequencies. The noise level of the bottom cabinet, increases at the peak frequencies of the bottom cabinet cavity. The effects of sound propagation from the bottom cabinet of the refrigerator, due to vibration from the compressor in a rectangular cavity, in dictating the overall sound level of the refrigerator is considerable. For the end user, a quiet run is one of the most important criteria in refrigerator selection. Therefore, design of the bottom cabinet cavity, in where the compressor works and causes the noise problem, has a profound significance. The natural frequencies of the bottom cabinet cavity are investigated. Firstly, natural frequencies are determined with analytical method. Secondly, natural frequencies are determined with numerical analysis using the finite element model of the bottom cabinet cavity. Comparisons with the results of the analytical study verify the validity of the numerical solution. It is seen that finite element model of the bottom cabinet cavity is applicable. Finally, experimental study is carried out for validation of both models. It is seen that the sound pressure of the bottom cabinet of the refrigerator is higher at some frequencies. As a result, these frequencies are in close match with the natural frequencies of the bottom cabinet cavity of the refrigerator which can be determined with the analytical and numerical analysis.