Radical Guide Vane Design and Optimization

摘要

Turbofan engines are connected to the airframe by a pylon that crosses the bypass duct downstream of the fan. The presence of the pylon generates a potential field that influences the upstream flowfield. Distortion generated by the pylon can be detrimental to the fan stability and integrity, and as such it must be controlled. This work presents a new method for the two-dimensional design of fan outlet guide vane cascades in the presence of the potential flow distortion caused by the pylon. The method, based on surface singularities, is capable of mitigating the distortion while preserving the performance of the nominal cascade. Design targets are achieved by manipulating both airfoil geometry and position within the cascade. Because the distortions caused by the pylon obey essentially inviscid fluid mechanics, the variation in load and loss parameters across the cascade can be approximated surprisingly well with a singularity method. The design rationale of controlling the incompressible load distribution leads to cascades with uniform load and loss even when viscous and compressible effects are considered using high-fidelity computational fluid dynamics. The new approach provides a significant speed-up over methods based on computational fluid dynamics and is valuable as an initial design tool.