Design and analysis of broadband acoustic silencers

Acoustic silencers are widely used in ventilation and exhaust systems such as internal combustion engines, plenum chambers, air-conditioning equipments, power plant ducts and stacks, etc. Conventional silencers are mainly classified into dissipative and reactive type, depending on whether the incoming sound energy is converted into heat by means of absorbing materials or reflected back due to impedance mismatches. In practice, acoustic silencers are preferred with broadband attenuation performance, relatively simple structure, easy maintenance, whilst complying with various engineering constraints. This paper investigates into the feasibility of using a cascade sub-chamber scheme for the better design of acoustic silencers. Through a case study on a reactive silencer design, results show that the proposed design strategy produces a cascade silencer with desired broadband performance. A systematic silencer design methodology is then proposed, which offers a wider scope for various silencer design applications.