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Muffling Devices
Published in David A. Bies, Colin H. Hansen, Carl Q. Howard, Engineering Noise Control, 2018
David A. Bies, Colin H. Hansen, Carl Q. Howard
A muffler is often installed on an engine or item of equipment to reduce the exhaust noise at some distance from the exhaust outlet, so that it is less than a specified sound pressure level. The calculation methods in this chapter can aid in the acoustic design of a muffler. However, there is no unique optimal design for a muffler, as there are often a number of competing requirements. These can include the requirement that the muffler should provide high levels of noise attenuation, but not impose significant back-pressure or occupy a large space; the muffler should be lightweight, but not radiate sound from its structure.
Muffling Devices
Published in David A. Bies, Colin H. Hansen, Engineering Noise Control, 2017
David A. Bies, Colin H. Hansen
There are two types of resonator muffler – those that contain no sound absorbing material at all and those that include sound absorbing material in the resonator chambers. Those that contain no sound absorbing material at all have resonators with a relatively high Q, and many resonators are needed to cover a reasonable frequency range. A small amount of sound absorbing material in the resonator chambers will produce a muffler with much more uniform attenuation characteristics as a function of frequency than a muffler without sound absorbing material. However, the peak attenuation at some frequencies may not be as high as achieved by a resonator muffler with no sound absorbing material, for the case where an excitation frequency corresponds very closely to one of the side branch resonances.
Introduction
Published in Randall F. Barron, Industrial Noise Control and Acoustics, 2002
The exhaust noise from engines, fans, and turbines is often controlled by using mufflers or silencers in the exhaust line for the device. The muffler acts to reflect acoustic energy back to the noise source (the engine, for example) or to dissipate the acoustic energy as it is transmitted through the muffler.
Effect of cyclic high temperature fluctuations on the corrosion failure of S40900, S43036, S31635 and S44400 stainless steels
Published in Cogent Engineering, 2021
Automotive exhaust systems consist of piping connections that control the movement of heated reactive gases from the ignition chamber of a vehicular engine to the exhaust manifold and through the exhaust silencer to the pipe outlet (Ikpe & Abdulsamad, 2017). Failure due to corrosion of the exhaust system causes rupture; resulting in leakages within the internal components, noise issues due to acoustic changes and environmental pollution. The high temperature conditions of exhaust systems coupled with the presence of dissolved corrosive anions necessitate cautious material choice in the production of exhaust system components for optimum and long lasting performance. The exhaust muffler is a component of an automobile exhaust system whose major functionality is to reduce the rumble passed out by the exhaust gases of an internal ignition chamber. It has an exterior shell, inner plates, inner pipes, end plates and other components. The temperature of exhaust mufflers is around 300°C to 500°C, but it can also handle higher temperatures up to 1200°C. Stainless steels are utilized in the production of automobile exhaust silencers due to their resilience to corrosion, high temperature stability and exquisite quality. Corrosion is the major factor responsible for the limited lifespan of automobile silencers and other parts of the automotive exhaust system (Hoffmann & Gümpel, 2009). Corrosion reactions control the chemical characteristics of the steel and greatly alter their physical and mechanical attributes.
Control of carbon dioxide emission in automobile vehicles using CO2 scrubber
Published in International Journal of Ambient Energy, 2019
V. S. Shaisundaram, M. Chandrasekaran, S. Mohan Raj, R. Muraliraja, T. Vinodkumar
In an automobile, a muffler is commonly known as ‘silencer’, this word is often misinterpreted as a system that serves the purpose of noise reduction alone. A muffler is that part of the exhaust system of an automobile that has been specifically designed to reduce the noise before letting it into the atmosphere. The pressure reduction is done in a way that back pressure is not developed, eventually not reducing the performance of the engine (Prasad and Crocker 1983).