Eric D. Wilson
Vibron Ltd., 1720 Meyerside Dr., Mississauga, ON L5T 1A3, Canada
Gas turbines are becoming common power producers in small to medium scale power plants. However, the environmental noise impact due to the proximity of these plants to urban centers has become a critical concern and large amounts of silencing are required. Passive and/or reactive elements are commonly used to silence the noise propagating from the turbine exhaust stack. Two factors, namely temperature and low-frequency dominance of the sound spectrum, must be properly accounted for in the silencer design. Simple conventional designs must include the effects of the above two parameters so that appropriate modifications can be incorporated to provide the necessary insertion loss. In this paper, performance evaluation of a passive silencer as well as a reactive silencer using numerical methods will be presented. Finite-element methods (FEM) have been successfully used to predict the performance of passive silencers. Details of the FEM procedure and the necessary temperature modifications will be highlighted. Boundary element methods (BEM) were applied to evaluate the performance of a reactive silencer. Simple tests to verify the results of the multidomain BEM methods were conducted. The results of the BEM procedure and the temperature modifications will also be presented in this paper.