Impact of Operating Conditions on Rotor/Stator Interaction of a High-Pressure Ratio Centrifugal Compressor

TitleImpact of Operating Conditions on Rotor/Stator Interaction of a High-Pressure Ratio Centrifugal Compressor
Publication TypeConference Paper
Year of Publication2022
AuthorsLottini F, Agnolucci A, Pinelli L, Pacciani R, Toni L, Guglielmo A, Grimaldi A
Conference NameASME Turbo Expo 2022 Turbomachinery Technical Conference and Exposition
PublisherASME
Conference LocationRotterdam, The Netherlands: June 13 – 17, 2022
Abstract
The current design trend of centrifugal compressors is aimed
at obtaining compact machines with high pressure ratios and
performance. This leads to high circumferential speeds and
lighter components, thus increasing static stresses and dynamic
forcing due to rotor/stator interactions. Therefore, the aeromechanical
characterization of these machines is a fundamental
step of the design chain. This paper presents an in-depth aeromechanical
study of a high-pressure ratio centrifugal compressor
using CFD. Firstly, the computational setup is validated against
the experimental data; then, the same numerical setup is used
to characterize the aeromechanical interactions between the impeller
and the upstream and downstream static components. The
URANS simulations are carried out at three different operating
points (near stall, design, near choke), and the unsteady
flow field is time and space decomposed showing higher forcing
functions at near stall and near choke conditions with respect
to the design point, as confirmed by the experimental acquisitions.
The presented results highlight the importance of extending
the aeromechanical evaluations to different operating points
in order to avoid unexpected vibration responses when operating
at off-design conditions. Finally, by virtue of an acoustic
post-processing techniques, the unsteady pressure coupling in
the inter-row region is analyzed to discern the main sources of
the overall unsteady interaction.
Notes

ASME paper GT2022-82108