Simulation Study on Engine Nozzle and Afterbody Drag Characteristics of Flying Wing Configuration

Abstract In order to study the characteristics of engine exhaust system and afterbody drag of flying wing aircraft, and explore the methods and characteristics of nozzle characteristics and afterbody drag increment in the determination of engine available thrust, the performance characteristics of serpentine nozzle and the determination methods of afterbody drag increment of flying wing configuration and serpentine nozzle were studied based on CFD simulation method, taking Serpentine two-dimensional tail nozzle and B-2 aircraft fuselage model as the research object. The results show that the discharge coefficient and thrust coefficient of the double S curved 2-D nozzle are smaller than those of the axisymmetric nozzle with the same inlet/outlet area ratio, and the maximum difference of thrust coefficient is 4.0%; The nozzle pressure ratio affects the afterbody drag of the flying wing configuration. When the flight Mach number is small, the afterbody drag increases with the increase of the pressure ratio. When the Mach number is large, the afterbody drag decreases with the increase of the pressure ratio; The database of afterbody drag coefficient increment under other engine conditions is established by CFD method, and the afterbody drag increment under a certain flight condition is predicted accordingly. The research method and results have important reference value for determining the installation net thrust of power plant with this kind of layout.