Engine behavior in Windmilling conditions

The aim of this project is to analyze the behavior of the low pressure compressors of a turbofan in Windmilling conditions, in order to derive a proper model for their performances. The objective is to improve the representativeness of an existing performance model for Windmilling prediction, which includes some artificial calibrations of the modules to fit experimental results. For that purpose, the behavior of Fan, Splitter, OGV, Booster and VBV at Windmill is analyzed. Steady 3D RANS simulations are performed on the assembly comprising Fan, OGV and Booster (Figure 1) to generate the Fan and Booster maps. To incorporate them in the model, the MFT (Map Fitting Tool) technique is used. A comparison with Lattice Boltzmann Method (LBM) simulations is carried out to study the effects of turbulence modeling and unsteadiness on performances. LBM is also used to evaluate the impact of bleed valves on the aerodynamic behavior of the LP compressor assembly and to calculate the engine BPR.