Acoustically Induced Vibration Generated by Multi-Hole Restriction Orifices in a Fuel Gas Piping System

Abstract Large noise and high frequency vibrations were observed in the piping downstream of the multi-hole restriction orifices (RO) in a fuel gas system of a gas processing facility. Through field measurements, it was found that the dominant frequency range of the vibration was above 1,000 Hz with a broad band characteristic, which is a typical characteristic of Acoustically Induced Vibration (AIV) excited by the noise from the pressure reducing devices. Since the AIV could be a threat to the structural integrity of the piping system and therefore a concern for the safe and reliable operation of the facility, detailed assessments were performed and countermeasures were implemented to address these issues. In this study, the noise prediction method specified in IEC standard (IEC 60534-8-3) was used with the valve correction factor for acoustical efficiency which has been developed for multi-hole orifice plates in the experimental investigations published in the paper previously. The accuracy of the proposed noise prediction method was verified by field measurements in the facility under the wide range of operating conditions. In addition, the public domain AIV assessment methods were investigated by using the filed measurement results to discuss the applicability of those methods under the specific conditions. It was found that attention should be paid to the evaluation of AIV when the pipe wall thickness is thin even in the region where the calculated sound power level is marginal.