Effect of Extended Inlet and Outlet Lengths on Transmission Loss of Double Expansion Chamber Reactive Muffler

Abstract

Internal combustion engines are one of the major causes of noise emissions. As in different industrial equipment, locomotives, and vehicles, the engines have a wide application base. Exhaust noise and noise that is created due to friction of different parts share the extreme input to noise pollution. A muffler is a means used by the exhaust system to reduce noise. For the reduction of noise, it is placed alongside the exhaust pipe. The decrease in the exhaust noise level is controlled by muffler construction and operating techniques. Therefore, the muffler configuration plays an important role. In this research work, an effort has been made to study the effect of parameters like different lengths of Extended Outlet (EO) for constant lengths of Extended Inlet (EI) elements in both chambers of Double Expansion Chamber (DEC) reactive muffler with an external connecting tube on transmission loss. It is observed that, as the length of EO is increased from L/5 to L/3 keeping EI constant, the average transmission Loss for the models decreases. The acoustic performance of the muffler is assessed by using COMSOL Multi-Physics and experimental validation.