Turbofan Nose Cone Interactions With Inlet Swirl

With highly integrated airframe architectures emerging as the leading concept of next generation aviation vehicles, research is needed to understand the interactions between inlet swirl distortions and turbofan engines. To meet these research demands, a computational fluid dynamics investigation was conducted to monitor the streamwise development of a complex swirling velocity field in the inlet duct of a turbofan engine with and without the presence of the turbofan nose cone component. By modeling the two geometric setups, natural fluid development and forced fluid/nose cone interactions were distinguishable. To validate the model, computational results were compared to existing experimental data at the fan rotor inlet plane. With the nose cone included, flow angle and swirl intensity predictions from the computational approach agreed well with the experimental measurements. The computational results were expanded upstream to demonstrate the effects of the nose cone geometry on the incoming swirl distortion. Radial flow angles in the presence of the nose cone began to vary from natural swirl development at approximately 0.25 fan diameters upstream, reaching a maximum difference near the leading edge of the nose cone component. Results from this investigation provided a validated model for the prediction of swirl development in a turbofan inlet duct in the presence of a nose cone. Significant change in the swirl profile development was shown from natural vortex motion to induced fluid/solid interactions.