CHOICE AND DESIGN OF A 3D FIXED-GEOMETRY INLET FOR A SMALL SUPERSONIC BUSINESS AIRCRAFT

摘要

The scheme and geometric dimensions of a three-dimensional (3D) self-starting fixed-geometry inlet of a supersonic business aircraft at a cruise flight speed of M_(cr)= 1.8 are chosen. Two variants of inlet positioning on the airframe are considered: (1) with ingestion of the boundary layer growing on the fuselage forebody and (2) with spillage of the boundary layer by mounting the inlet at a certain height above the fuselage surface. The flow over the inlet integrated with the airframe of the supersonic business aircraft is calculated by the FASTRAN software based on integration of the system of steady Reynolds-averaged Navier-Stokes equations, which uses an implicit scheme to describe the spatial flows of a viscous compressible perfect gas settling over time at constant specific heat in a Cartesian coordinate system. As a result, the local parameters of the flow along the inlet duct are obtained. The integral inlet performance (flow rate coefficient  and total pressure loss a along the inlet duct and at the subsonic diffuser exit) is also estimated. In order to enhance the integrated characteristics of the inlet and increase the range of stable operation of the inlet in throttling regimes, a system of boundary layer control is applied in the region of supersonic deceleration that bypasses some of the air through windows in the comer zones on the side walls (cheeks) and bleeds through slots in the throat region.