Investigation of a Compressor Rotor Non-Synchronous Vibration With and Without Fluid-Structure Interaction

Abstract

This paper study the non-synchronous vibration (NSV) of a high speed multistage axial compressor using rigid blade and vibrating blade with fluid-structural interaction (FSI). The unsteady Reynolds-averaged Navier-Stokes (URANS) equations and mode based structural dynamic equations are solved. A low diffusion E-CUSP Reimann solver with a 3rd order WENO scheme for the inviscid fluxes and a 2nd order central differencing for the viscous terms are employed. A 1/7th annulus sector of IGV-rotor-stator is used with a time shifted phase lag BC at circumferential boundaries. An interpolation sliding boundary condition is used for the rotor-stator interaction. The URANS simulation for rigid blades shows that the leading edge (LE) tornado vortices, roughly above 80% rotor span, travel backwards relative to the rotor rotation and cause an excitation with the frequency agreeing with the measured NSV frequency. The predicted excitation frequency of the traveling vortices in the rigid blade simulation is a non-engine order frequency of 2603 Hz, which agrees very well with the NSV rig testing. For the FSI simulation, the results show that there exist two dominant frequencies in the spectrum of the blade vibration. The lower dominant frequency is close to the first bending mode. The higher dominant frequency close to the first torsional mode agrees very well with the measured NSV frequency. The simulation conducted in this paper appears to indicate that the NSV is excited by the traveling vortex.

Investigation on the Mechanism and Parametric Description of Non-Synchronous Blade Vibration

“…The blade vibration is attributed to the oscillating blade tip vortex by Hwang et al [ 13 ]. By using the model of Kielb [ 14 ], studies have been carried out by Zha et al [ 15 , 16 , 17 , 18 , 19 , 20 ] to explore the flow at tips. The results reveal that the tip clearance shape has an influence on the frequency of NSV [ 15 ].…”

“…The oscillation by the vortex coming and leaving generates a torsion moment, coupling with the blade structure in modal vibration [ 18 ]. Simulations [ 19 , 20 ] coupled with fluid and structure studies indicate that the blade vibration exhibits a limit cycle oscillation excited by the aerodynamic force, but the comparison results also show that the first torsion mode observed in the rig test is accompanied by the first bending vibration of the blade, which is not obvious in the experiments.…”

A spatial–temporal analysis approach for flutter predictions using decoupled and fully-coupled methods

“…Vahdati et al [15] used the fully-coupled approach to explain the stall and acoustic flutter mechanisms of the wide-chord fan blade. Gan et al [16] adopted the fully-coupled fluid-structure interaction method to investigate the non-synchronous vibration of a compressor rotor. Phan and He [17,18] used the fully-coupled method to elucidate the vibration mechanisms of the structurally and aerodynamically mistuned cascade.…”

Investigation on the Flow Field Entropy Structure of Non-Synchronous Blade Vibration in an Axial Turbocompressor

“…Zha et al [ 14 , 15 , 16 , 17 , 18 , 19 ] carried out a series of works with the same compressor of Kielb [ 2 ], established 1/7th and full annulus models for the 1.5-stage compressor. The RANS simulations [ 14 ] show that the tip clearance shape has a strong influence on the frequency of NSV.…”

“…Pay attention to the interaction of fluid and structure, the applications of the time-domain FSI method have been taken into practice to research related contents. The computations [ 18 , 19 ] are conducted to investigate the NSV by comparing the flow excitation with rigid blades and the blade vibration with fluid–structure interaction. It is indicated that the NSV of the compressor is caused by the tornado-like tip vortex in the rotor tip as rotating flow instability.…”