Performance Study And Thermal Stress Analysis Of Exhaust Cooling Silencers

It is necessary to use the cooling silencer to reduce the diesel engine exhaust noise and cool the exhaust gas to restrain the infrared radiation. The purpose of this dissertation is to investigate the fluid performance, cooling effect, acoustic attenuation characteristics and structural thermal stress.The aerodynamic performance is one of the evaluated parameters of silencers. In this paper, the software FLUENT which is based on the finite volume method was used to analyse the fluid performance of two kinds of exhaust cooling silencers with and without consideration of cooling effect. The flow resistance loss, cooling effect and temperature field are determined. The internal fluid flow characteristics is analyzed also.Based on the internal temperature field calculated from CFD, the acoustic attenuation performance of exhaust cooling silencers at normal temperature and high temperature were calculated and analyzed by the finite element method and SYSNOISE software. The transmission loss characteristics is changed by reduce the volume of left resonance chamber of the two-inlet exhaust cooling silencers.Considering the bad working conditions of exhaust cooling silencers and the large gradient between the exhaust gas and cooling water, the local structure damage of the silencers may be occurred. In this dissertation, the finite element method software for the structure analysis ANSYS is used to calculate and analyze the thermal stress and strain of the exhaust cooling silencers. The thermal strain of silencers may be decreased effectively by adding supports between the layer.