OGV Tailoring to Alleviate Pylon-OGV-Fan Interaction

This paper studies the application of sensitivity analysis to the redesign of outlet guide vanes (OGV’s) in a commercial gas turbine engine. The redesign is necessitated by the interaction of the pylon induced static pressure field with the OGV’s and the fan, leading to reduced OGV efficiency and shortened fan life. The concept of cyclically varying camber is used to redesign the OGV row to achieve suppression of the downstream disturbance in the domain upstream of the OGV row. The harmonic nature of the disturbance and the tailoring permits the analysis for the redesign to be performed on only one blade passage. Sensitivity of the pressure field upstream of the OGV’s to changes in blade camber is computed, and used to modify the blade profile. The sensitivity is obtained from a linear perturbation CFD analysis; nonlinear CFD analysis and actuator disc theory (ADisc) provide validation at each step. The modifications reduce the pylon induced pressure variation at the fan by more than 70%. The presence of an interaction mechanism from the pylon to the OGV’s is investigated.Copyright © 1995 by ASME