Investigation on Acoustic Resonance for Different Diffuser and Effect on Centrifugal Compressor Pipeline Failure

Acoustic resonance (AR) can lead to pipeline or blade fatigue for centrifugal compressor. It must be considered during design. But investigation in this area is very limit, especially for the lack of experiment verifications. In this research, acoustic mode simulation analysis is investigated on three different diffusers for the same centrifugal compressor by LMS Acoustics calculation software. Meanwhile, pressure pulsation (PP) experiment is carried out to verify the correctness about AR calculation. The PP level will increase typically when the blade passing frequency (BPF) is close to the acoustic modal frequency for full-height vaned diffuser. Then, the modified diffuser for half-height vaned and vaneless are applied at the same test-bench and the results show PP level is obvious decreased. In other words, by changing the structure of diffuser could effectively avoid AR. Finally, the above results applied in the field of failure compressor unit could obviously reduce the level of high frequency vibration. This research reveals the failure mechanism for pipeline, and introduce an effective method to avoid AR. It can contribute to blade condition monitoring and the prohibition failure of centrifugal compressor.