Numeric prediction and comparison of sound radiation from hermetic compressors varying the housing thickness
Gabriela Cristina Cândido da Silva1; Maria Alzira de Araújo Nunes1
1 Universidade de Brasília
doi:10.20906/CPS/COB-2015-0973
Resumo
The acoustic characteristics of hermetic compressors are critical parameters for the adequacy and acceptance of this product on the market. It is essential to predict the radiated noise by such equipment still in the design phase and to evaluate design changes aiming mitigate it. In this context, numerical modeling becomes feasible to reduce the cost associated with the manufacture of prototypes and design time. In this work, the TPA (Transfer Path Analysis) technique is used to predict numerically the sound power radiated by two different compressor housing thicknesses (3.2 mm and 2.8 mm). In order to validate the method, the results for 3.2 mm are compared with experimental measurements and showed good agreement. A numerical analysis of the vibro-acoustic energy trajectory between the sound source (four springs and discharge tube) and the receiver (microphones) is done in order to assess the contribution of different noise propagation paths. The results show that discharge tube path has the bigger contribution to the radiated noise and small changes in thickness are enough to change the level of noise radiated by the compressor in different frequency bands. The TPA is shown as a useful and viable tool for investigation of radiated noise by compressors and allows even identify operating ranges with more sensitivity. Thus, new changes in the acoustic design in order to minimize the noise may be proposed efficiently according to the most significant contribution to the receiver, cost and manufacturing process.
Palavras-chave: Hermetic compressor; TPA technique; radiation; simulation