muffler design with baffle effect and perforations on transmission loss

Reactive mufflers depend on reducing the exhaust noise through a volume depending on reflection of sound noises. muffler analysis is always challenging task due to complex design, shape and size limitation for specific application. that is why the reduction of exhaust noise generated from engine is in today's world an important issue. attaching a muffler in the exhaust pipe is the good option for reducing noise. but muffler requires specific design and construction considering various noise parameters produced by the engine. since early development of mufflers, the main objective of design was attenuation of sound in regular mufflers. a typical sound generated by vibrational waves is usually based on the experience and design experience, which can be enhanced by optimizing the internal structure of the exhaust system. the use of baffles and perforations has a significant effect on reducing the transmission loss in a silencer exhaust system. in order to evaluate the response effect of a silencer, the effect of baffle and perforations, without baffles and perforations, was evaluated in comsol5.2 software. which results in numerical results with close experimental results and the effect of baffle and perforations, have shown a good reduction in transmissibility, and their partial differences are due to the features of geometry design.