A supersonic through-flow fan engine airframe integration study (original) (raw)

1989, Aircraft Design and Operations Meeting

A study is undertaken to investigate the engine airframe integration effects for supersonic through-flow fan engines installed on a Mach 3.20 supersonic cruise vehicle. Six different supersonic throughflow fan engine installations covering the effects of engine size, nacelle contour, nacelle placement, and approximate bypass plume effects are presented. The different supersonic through-flow fan installations are compared with a conventional turbine bypass engine configuration on the same basic airframe. The supersonic throughflow fan engine integrations are shown to be comparable to the turbine bypass engine configuration on the basis of installed nacelle wave drag. The supersonic throughflow fan engine airframe integrated vehicles have superior aerodynamic performance on the basis of maximum liftto-drag ratio than the turbine bypass engine installation over the entire operating Mach number range from i.i0 to 3.20. When approximate bypass plume modeling is included, the supersonic through-flow fan engine configuration shows even larger improvements over the turbine bypass engine configuration. NOMENCLATURE BPR bypass ratio CD drag coefficient, D/gS CL lift coefficient, L/qS D drag L lift M Mach number q dynamic pressure S reference area Subscrip__ f friction w wave INTRODUCTION In perusing the technologies required for efficient long range supersonic cruise aircraft, NASA has sponsored a number of studies to identify suitable propulsion system concepts. In the past, conventional and variable cycle engines were considered the most likely candidates. With renewed *Supervisor, Aerospace Analysis Section, Member AIAA Another desirable aspect of the engine cycle is that the bypass ratio decreases with increasing flight Math number, providing higher cruise thrust. Reference 3 shows that much of the improved specific fuel consumption for supersonic through-flow fan engines results from potential improvements in installation efficiencies for long range supersonic cruise applications. The possible improvements in inlet performance with supersonic through-flow fan engines has been shown in reference 4. This study addresses the engine airframe integration characteristics for supersonic through-flow fan propulsion systems, six different supersonic through-flow fan engine installations are examined in this study. The effects of engine size, nacelle contouring, nacelle placement, and approximate bypass plume modeling are investigated. Additionally, the supersonic through-flow fan (STFF) nacelle installations are compared with a conventional turbine bypass engine (TBE) nacelle installation on the basis of installed wave drags and maximum lift to drag ratios for complete engine airframe the