Historically, designs of centrifugal compressor systems focused on the aerodynamic and performance aspects. Noise, pulsation, and vibration phenomena were rarely considered. Recent applications of high flow and high power centrifugal compressors require that this approach be changed. Several transmission system failures, in different gas transmission companies, were documented. They included fatigue failures of the compressor components, piping attachments, and, in some instances, pipework shell failures. As a result, numerous investigations were carried out. While the compressors were adequately designed from the aerodynamic performance point of view, they appeared to act as dynamic generators, producing excessive noise, pulsation, and vibration levels even when operated well within their design parameters. It was found that neither the designers nor equipment users had a clear understanding on how to practically analyse and mitigate such dynamic phenomena.
The objective of this study is to briefly explain possible sources of the observed problems in the hope that such explanation might provide a means for preventing or minimising noise and pulsation generation in centrifugal machines. The study is based on the author’s experience in mitigating pulsation/noise and vibration problems mainly in the single stage natural gas centrifugal compressor systems. The study briefly describes differences in operation between vaned and vaneless diffuser compressors. It considers pipework and its influence on the compressor dynamic performance, and addresses some aspects of the compressor design in both aerodynamic and acoustic areas. Furthermore, it gives several practical methods to mitigate high frequency pulsation and vibration problems. Most of the approaches suggested here were implemented in the field and evaluated either by the author or others.
