Transmission loss of a piping network

Abstract

This paper describes a numerical procedure developed to analyze piping and duct systems. The procedure combines transfer matrix and finite element methods and was used to predict the transmission loss of a piping network constructed of rigid‐walled, square cross‐section tubing. The network consisted of one input, one output, and several segments made up of straight pipes and 90° elbows. These were interconnected at several “T” junctions. The junctions and elbows were treated using finite element models that took into account two‐dimensional wave propagation. These were connected to straight pipes in which one‐dimensional wave propagation was assumed. This led to a much reduced connective matrix for each finite element model. The solution of the entire network was then obtained by solving a relatively small system of linear equations. Experimental measurements of the network transmission loss were made using a two‐microphone transfer function technique with random “white” noise and a dual channel FFT analy...