Flow Distortion Into the Core Engine for an Installed Variable Pitch Fan in Reverse Thrust Mode

Abstract The flow distortion at core engine entry for a variable pitch fan (VPF) in reverse thrust mode is described from realistic field obtained using an integrated airframe-engine model. model includes the VPF, splitter, complete bypass nozzle path wrapped nacelle, and installed to airframe landing configuration through pylon. A moving ground plane mimic rolling runway included. 3D Reynolds-averaged Navier–Stokes (RANS) solutions are generated two combinations of VPF stagger angle rotational speed settings entire aircraft run 140 20 knots. internal characterized by lip separation, pylon wake, recirculation turned back VPF. portion stream turns 180 deg with separation splitter leading edge feed engine. exhibits circumferential radial nonuniformities that depend on development different speeds. temporal dependence distorted features also explored unsteady (URANS) analysis. Total pressure swirl descriptors, as defined Society Automotive Engineers (SAE) S-16 committee, and, total loss into operating conditions It observed intensity critical operation, while within acceptable limits. Therefore, baseline sharp replaced larger rounded edges radii, ∼0.1x ∼0.2x times duct height. This was found reduce levels. description distortion, this study, necessary ascertain stable which powers mode.