Damping acoustic pressure pulsations in pipelines using Helmholtz resonators

Abstract

In industrial piping systems, centrifugal and reciprocating turbomachinery generate acoustic pressure pulsations, which propagate into the pipeline and interact with piping components, potentially causing vibrations, increased fretting wear, and even fatigue failure. In this thesis, an acoustic damping device known as the Helmholtz resonator (HR) is experimentally studied. The effects of HR cavity volume, pipeline diameter, HR location, the use of multiple HRs, and mean flow velocity are investigated to determine their effects on the acoustic attenuation achieved within a pipeline. Measurements are also performed to clarify the mechanism of attenuation and the effects of incident pressure amplitude on the transmission loss of an HR. The findings of this thesis may be used as practical guidelines for the use of HRs in industrial systems, where characterizing the acoustics is usually difficult and costly, and the available space for damping devices may be limited.