The aeroelastic instability known as buffeting is characterized as the structural response to aerodynamic excitations caused by self-sustaining flow instabilities. In the more aggressive architectures of modern high-bypass aero engines outlet guide vanes (OGVs) are being deployed closer to the fan. Buffeting of OGVs leads to increased losses within the low pressure system and can cause structural fatigue. This study seeks to make practical the use of CFD in predicting OGV buffeting regions on an engine’s operating map without the need for costly unsteady simulations at all points. Additionally, aeroelastic simulations are carried out to examine the link between the aerodynamics and structural response of OGV buffeting. Predictions were made by linking steady loss metrics, derived from comprehensive Reynolds-Averaged Navier-Stoke (RANS) simulations, with unsteady RANS (URANS) simulations of confirmed OGV buffeting conditions. This was followed by the aeroelastic parametric study, to determine the instability’s most influential parameters. The URANS results confirmed the cause of OGV buffeting as transonic buffet, exhibiting unsteady shock movement, fluctuating separation and a shockwave-boundary-layer-interaction. The unsteady pressure variations unique to OGV buffeting were found to be well predicted using steady loss metrics and that the phenomenon itself is most readily driven by low pressure system inlet Mach number with flow incidence playing a secondary role. 


Investigating the Causes of Outlet Guide Vane Buffeting

Division / Sponsor:
International Gas Turbine Institute (IGTI)

Paper Proceedings: https://asmedigitalcollection.asme.org/GT/GT2020/volume/84058

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