Numerical examination of lock-in hypothesis of non-synchronous vibration in an axial compressor

Jiaye Gan, Hong Sik Im, GeCheng Zha

Research output: Chapter in Book/Report/Conference proceedingConference contribution

Abstract

This paper examines the lock-in hypothesis of nonsynchronous vibration (NSV) in a high speed multistage axial compressor. The unsteady Reynolds-averaged Navier-Stokes (URANS) equations and modal approach based structural dynamic equations are solved. A low diffusion E-CUSP approximate Riemann solver with a 3rd order WENO scheme for the inviscid fluxes and a 2nd order central differencing for the viscous terms are employed. The structural vibration of the blades are solved by a set of modal equations that are fully coupled with the flow equation. The rigid blade simulations are conducted to examine the main driver of NSV. A 1/7th annulus sector of IGVrotor-stator is used with a time shifted phase lag BC at circumferential boundaries. A dominant excitation frequency caused by the traveling tip vortices are captured. The excitation frequency is not on the engine order. The simulation is then switched to fluid structure interaction that allows the blades to vibrate freely under the flow excitations. The matching of aerodynamic forcing frequency with the structure response frequency seems indicating that the NSV of this compressor is a limit cycle oscillation (LCO) excited by aerodynamic forcing, not caused by flow frequency/phase locked to structural frequency. The rotating speed is varied within a RPM range, in which the rig test detected the NSV. The unsteady flows with rigid blades are simulated first at several RPMs. The simulation indicates that the structure response follows the frequency of the flow excitations existing in the rigid blades. At least under the simulated conditions, the NSV does not appear to be a lock-in phenomenon, which has the flow frequency lock-in to the structure natural frequency.

Original languageEnglish (US)
Title of host publicationStructures and Dynamics
PublisherAmerican Society of Mechanical Engineers (ASME)
Volume7B-2017
ISBN (Electronic)9780791850930
DOIs
StatePublished - 2017
EventASME Turbo Expo 2017: Turbomachinery Technical Conference and Exposition, GT 2017 - Charlotte, United States
Duration: Jun 26 2017Jun 30 2017

Other

OtherASME Turbo Expo 2017: Turbomachinery Technical Conference and Exposition, GT 2017
CountryUnited States
CityCharlotte
Period6/26/176/30/17

ASJC Scopus subject areas

  • Engineering(all)

Fingerprint Dive into the research topics of 'Numerical examination of lock-in hypothesis of non-synchronous vibration in an axial compressor'. Together they form a unique fingerprint.

  • Cite this

    Gan, J., Im, H. S., & Zha, G. (2017). Numerical examination of lock-in hypothesis of non-synchronous vibration in an axial compressor. In Structures and Dynamics (Vol. 7B-2017). American Society of Mechanical Engineers (ASME). https://doi.org/10.1115/GT2017-65244