Numerical Assessment of One-Chamber Plenums Lined with Multi-Layer Sound Absorbers Using a Particle Swarm Method

Abstract

High noise levels can be harmful to workers and can lead to psychological and physiological ailments. Consequently, noise control in an industrial setting is vital. Acoustical plenums have been widely used in depressing industrial venting noise. Because of the constrainment problem in practical engineering work, there is a growing need to optimize acoustical performance within a fixed space. However, research work of shape optimization on a space-constrained acoustical plenum by adjusting the design parameters has been neglected. In addition, the optimal mechanism of internal sound absorbers within the plenum has been ignored. In order to efficiently design a better performancing acoustical plenum with minumum manufacturing costs, a numerical assessment used to search for an optimally shaped one-chamber acoustical plenum lined with four kinds of multi-layer sound absorbers (one-layer, two-layer, three layer, and four-layer) in conjunction with a particle swarm method ( PSO) will be introduced. Before dealing with a broadband noise, a reliability check of the PSO method by maximizing the sound absorption coefficient ( α) for a three-layer sound absorber at a pure tone (500 Hz) will be performed. Consequently, this paper provides a quick economical, and effective method for reducing noise levels by optimally designing a shaped one-chamber acoustical plenum lined with multi-layer sound absorbers using a particle swarm method.