Impact of Ultra-High Bypass/ Hybrid Wing Body Integration on Propulsion System Perrformance and Operability (Invited)

Computational studies have been carried out to assess engine operability for an Ultra High Bypass (UHB) engine installation on a Hybrid Wing Body (HWB) aircraft. In this installation the engines are mounted on the upper aft fuselage. At certain aircraft operating conditions at the boundary of the flight envelope, such as 0.2 flight Mach with very high angle of attack or takeoff with 30 knot crosswind, the installed engine flowfield and inlet distortion may differ from what has been typical for conventional tube+wing aircraft with underwing podded engines. Definition of inlet distortion at these key operating conditions for this configuration was provided by the airframer. The engine response to the inlet distortion was computed based on a coupled inlet-fan CFD simulation. Separate analyses were performed to assess performance, fan operability, core engine operability, and fan blade vibratory stress.