Muffler Research Paper

The paper shows the measurement of the acoustical transmission loss of rectangular cross section expansion chamber muffler with various aspect ratio of cross section. A muffler (silencer) is an important noise control element for reduction of machinery exhaust noises other noise sources which involves the flow of gases. Mufflers are typically arranged along the exhaust pipe as the part of the exhaust system of an internal combustion engine to reduce its noise. The wave 1-D used as a simulation tool.

Keywords: Rectangular Cross Section Muffler, FEA Acoustic Module- wave 1-D, Sound Transmission loss,

1. INTRODUCTION

The UK based term muffler (silencer in English, or back box in Irish English) is a device for reducing the amount of noise emitted by the exhaust of an internal combustion engine [1].Mufflers are mostly used to reduce noise related with internal combustion engine exhausts, high pressure gas or steam vents, compressors and fans. These examples lead to the conclusion that a Muffler allows the passage of fluid while at the same time restricting the free passage of sound. The greatest source of noise which disturbs people and creates impact on their environment comes from transport vehicles [2]. The huge increase in mobility achieved by technological development in the last century accompanied by high background noise levels, particularly due to road traffic, has become a feature of our society.

A dissipative muffler uses sound absorbing material to take energy out of the acoustic motion in the wave, as it propagates through the muffler. Noise levels of more than 80 dB are injurious for human beings [3]. Hence to reduce noise from internal combustion engines they are equipped with an important noise control element known as silencer or exhaust muffler which suppresses the acoustic pulse generated by the combustion processes