Excess vibration and noise on gas turbine exhaust silencer

Abstract

This particular gas turbine silencer experience excess vibration at a critical operating condition especially on a large powerplant applications. The vibrations seem to be more pronounced on cold winter days when the turbine load exceeds 110 MW. The excess vibration disappeared when it passed the critical operating condition to its maximum load 113 MW. The 18.5 Hz mode dominated the vibration spectrum. The mode consisted of a rocking motion of the entire silencer and a local deflection of the silencer walls. The experimental mode shapes corresponding to the 18.5 Hz will be discussed. A CFD (Computational Fluid Dynamics) analysis will be used to assess the flow-induced vibration problems.