Optimum Design of Exhaust System of a Ship

Şadi Kopuz, Hasan Avşar, Nasser Ghassembaglou, Levent Kavurmacıoğlu (Enginsoft Turkey)

CHALLENGE - The study focus on the design of exhaust system belonging to a diesel engine of a ship. A 3-dimensional model of the system has been constructed and, the Computational Fluid Dynamics (CFD) analyses covered the flow mechanism of back pressure. For the silencer design, acoustic characteristics have been determined by applying an empirical methodology. 

SOLUTION - The dimensions and internal structure of the silencers which are the main components of the exhaust system and physical properties of insulation material have been determined based on acoustics, back pressure and the layout of the diesel engine in an engine room. Therefore, design criteria include noise reduction (>25 dBA), back pressure (<50 mbar), and dimensional limits. A methodology for optimizing the acoustics and back pressure at the same time was realized by using optimization platform modeFRONTIER. The integration of parametric CFD Analysis into modeFRONTIER brought optimal results.

BENEFITS - Results show a decrease of the noise level in the final design of the silencer, with the acoustic output from 98.5 dB reduced to 96.7 dB. The pressure difference is also notable, with the final design characterized by lower pressure of 1057 Pa.