Gas turbines are used with increasing frequency in power plants. At the same time, the acoustic requirements for these plants have been continuously increased. Consequently, silencers are required for almost all installations that particularly include gas turbines and heat recovery steam generators. The noise level from turbines is typically high, especially at low frequencies. Gas turbine silencers are especially designed to work in an environment where they are simultaneously exposed to high temperatures and to high velocity turbulent flow.
The silencers can be placed directly behind gas turbine in the by-pass stack and/or at the heat recovery steam generator outlet. Silencers on the suction and exhaust side of large fans and compressors are normally absolutely essential. But in these cases the materials' thermal and mechanical requirements are much less. In most cases, absorption silencers are used. Regarding the requirements, the design of the silencers is based on the working conditions and the noise data given.
The following elements have to be taken into consideration: