Vibro-acoustics of a pipeline centrifugal compressor

Structural vibration and noise radiation of a single-stage centrifugal compressor excited by the internal unsteady flow is investigated experimentally in the first part of our work [Zhou et al. Appl Acoust 2018;131:112-28]. Experimental results for acceleration of vibration and sound pressure under different rotational speeds indicate that the straight discharge pipe connecting the volute is forced to vibrate the most intensively at the blade passing frequency (BPF) and acts as the major contributor to the compressor noise emission. In this paper, a pipe micro-perforated panel (PMPP) is optimally designed with the genetic algorithm to suppress vibration and noise radiation of the straight discharge pipe section. A maximum sound pressure level (SPL) reduction of 20 dB for the BPF component and 8 dB for the overall noise are observed under the tested working conditions, while the influence of the PMPP on the aerodynamic performance of the compressor is negligible. The PMPP may be a promising method for controlling the tonal component of vibro-noises radiated from the centrifugal compressor.